DERIVES D'ACIDES AMINES

AMINO ACID DERIVATIVES AND A PROCESS FOR THE PREPARATION THEREOF

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
Novel compounds of the general formula (I),
<IMG> (I)
and their salts and optically active isomers have been pre-
pared. The new compounds according to the invention possess
valuable pharmacological and therapeutical properties.
In the above formula
A1 stands for hydroxy, C1-4 alkoxy, cycloalkoxy, aralkoxy,
substituted aralkoxy, aryloxy, substituted aryloxy or
a group of the general formula -NR?4 or <IMG>
wherein
R14 is hydrogen, C1-4 alkyl or aralkyl,
R6 is hydrogen, C1-5 alkyl, aralkyl, hydroxyl-substituted
aralkyl, heteroaralkyl or a group of the general
formula <IMG>
Y is hydroxy, amino, alkylamino, dialkylamino, C1-4 alk-
oxy or aralkoxy, and
r is an integer of from 1 to 10 or an average polymeriza-
tion grade of up to 2000,
B1 is a group of the formula -SO2OH, -OSO2OH, -O-PO(OH)2
or -S-S-R-11, wherein
R11 is C1-4 alkyl, aralkyl or aryl or a residue obtained
when removing group B1 from the general formula (I),
R stands for hydrogen, C1-4 alkyl or aralkyl,
R? stands for hydrogen or halogen,

R1 stands for hydrogen C1-4 alkyl, aryl, aryl having a nitro
or alkoxy substituent, aralkyl, substituted aralkyl,
alkoxycarbonyl, aralkoxycarbonyl, aralkoxycarbonyl having
a halogen, alkoxy, nitro, phenylaso, or alkoxyphenylaso
substituent, alkyl-substituted aryloxycarbonyl, acyl,
benzoyl, arylsulfonyl or -(NH-??-CO)p group (wherein R6
has the same meanings as defined above and p is an integer
of from 1 to 10 or an average polymerization grade of up
to 2000), or a -CO- group,
R2 stands for hydrogen, C1-4 alkyl, aralkyl or a -CO- group,
but if R1 and R2 each stand for a -CO- group, they form
a ring through an o-phenylene, alkylene or -CH=CH- group,
R3 stands for hydrogen, carboxy or carbalkoxy,
R4 stands for hydrogen, halogen C1-4 alkyl or hydroxy,
R5 stands for hydrogen, halogen, C1-4 alkyl, carboxy, carbox-
amino, carbalkoxy or carboaralkoxy,
n is 1, 2 or 3,
n is 1, 2, or 4,
s is 0, 1, 2, 3 or 4, and
t is 1, 2 or 3.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of a compound of the general
formula (I)
<IMG>
(I)
wherein A1 stands for hydroxy, C1-4 alkoxy, cycloalkoxy, aralkoxy,
substituted aralkoxy, aryloxy, substituted aryloxy or a group of the
general formulae-NR14 or <IMG> wherein R14 is hydrogen, C1-4
alkyl or aralkyl, R6 is hydrogen, C1-5 alkyl, aralkyl, hydroxy-substituted
aralkyl, heteroaralkyl or a group of the general formula
<IMG>
<IMG> , y is hydroxy, amino, alkylamino, dialkylamino, C1-4alkoxy
or aralkoxy, and r is an integer of from 1 to 10 or an average polymerization
grade of up to 2000, B1 is a group of the formulae -SO2OH, -OSO2OH,
-O-PO(OH)2 or -S-S-R11, wherein R11 is C1-4 alkyl, aralkyl or aryl or a
residue obtained when removing group B1 from the general formula (I), R
stands for hydrogen, C1-4 alkyl or aralkyl, Rx stands for hydrogen or
halogen, R1 stands for hydrogen, C1-4 alkyl, aryl, aryl having a nitro or
alkoxy substituent, aralkyl, substituted aralkyl, alkoxycarbonyl, aralkoxy-
carbonyl, aralkoxycarbonyl having a halogen, alkoxy, nitro, phenylazo or
alkoxyphenylazo substituent, alkyl-substituted aryloxycarbonyl, acyl, benzoyl,
arylsulfonyl or <IMG> group (wherein R6 has the same meanings as
defined above and p is an integer of from 1 to 10 or an average polymeriza-
tion grade of up to 2000), or a -CO- group, R2 stands for hydrogen, C1-4
alkyl, aralkyl,or a -CO- group, but if R1 and R2 each stand for a -CO-
42

group, they form a ring through an o-phenylene, alkylene or -CH=CH-
group, R3 stands for hydrogen, carboxy or carbalkoxy, R4 stands for hydrogen,
halogen, C1-4 alkyl or hydroxy, R5 stands for hydrogen, halogen, C1-4
alkyl, carboxy, carboxamido, carbalkoxy or carboaralkyloxy, m is 1, 2 or
3, n is 1, 2, 3 or 4, s is 0, 1, 2, 3 or 4, and t is 1, 2 or 3, or a salt
or an optically active isomer thereof, in which
a) if a compound of the general formula (I) containing a free
primary amino group is to be prepared, the protecting group of a compound
of the general formula (II)
(II)
<IMG>
wherein R3, R4, R5, Rx, R, B1, n, m, s and t each have the same meanings as
defined above, R7 stands for aralkyl, formyl, trifluoroacetyl, p-toluene-
sulfonyl or -CO- group or a group of the general formulae R15-OCO- or
<IMG> , wherein p and R6 each have the meanings as defined above, and
is C1-4 alkyl, cycloalkyl, aralkyl, substituted aralkyl, aryl or
substituted aryl, and R8 stands for hydrogen or -CO-, but if R7 and R8
each stand for a -CO- group, they form a ring through an O-phenylene,
alkylene or -CH=CH- group, is split off by acidolysis, hydrogenolysis,
treatment with sodium, treatment with sodium amide, treatment with
hydrazine, treatment with dilute ammonium hydroxide, or enzymatic hydrolysis;
or
b) if a compound of the general formula (I) containing a free
carboxy group is to be prepared, a compound of the general formula (III),
<IMG> (III)
43

wherein R, R3, R4, R5, Rx, B1, n, m, s, and t each have the same meanings
as defined above and A2 stands for a C1-4 alkoxy, aralkoxy or substituted
aralkoxy group or a group of the general formulae <IMG> or <IMG>
(wherein R6, Y and r each have the same meanings as defined above, and R16
is hydrogen, C1-4 alkyl or aralkyl), is subjected to saponification,
acidolysis, hydrogenolysis or enzymatic hydrolysis; or
c) if a compound of the general formula (I) containing a free
primary amino group and a free carboxy group is to be prepared, the protect-
ing groups attached to the .alpha.-amino group and the .alpha.-carboxy group of a com-
pound of the general formula (IV),
(IV)
<IMG>
wherein R3, R4, R5, Rx, R, B1, n, m, s and t each have the same meanings
as defined above, R9 stands for aralkyl, formyl, p-toluenesulfonyl or a
group of the general formulae R15-OCO- or <IMG> (wherein R15, R6
and p each have the same meanings as defined above), and A3 stands for
C1-4 alkoxy, aralkoxy, substituted aralkoxy, or an aralkoxy, -NR?6 or
<IMG> group attached to a solid polymer matrix (wherein R16, R6,
r and Y each have the same meanings as defined above), are split off
simultaneously by acidolysis, alkaline hydrolysis, hydrogenolysis, treatment
with sodium, treatment with sodium amide or enzymatic hydrolysis; or
d) if a compound of the general formula (I) containing sulfonyl,
sulfonyloxy or phosphoryloxy group is to be prepared, a compound of the
general formula (V),
44

<IMG> (V)
wherein R1, R2, R3, R4, R5, Rx, R, A1, n, m, s and t each have the same
meanings as defined above and B2 is halogen, hydroxy, p-toluenesulfonyloxy,
or a group of the formulae -SH, -SO-OH or -SO2R10, wherein R10 is C1-4
alkoxy or aralkoxy, is oxidized, hydrolysed, reacted with an alkali sulfite
or alkali bisulfite, or is esterified with sulfuric acid or phosphoric
acid or with a derivative thereof; or
e) if a compound of the general formula (I) containing a
sulfonyl group is to be prepared, a compound of the general formula (VI),
<IMG> (VI)
wherein R1,R2, R3, R4, A1, n and s each have the same meanings as defined
above, R12 stands for hydrogen, C1-4 alkyl, aralkyl, or -CH2-, and R13
stands for alkali metal, vinyl group, or -CH2- group, but when R12 and R13
each represent -CH2- group, they form together an aziridine ring, is
alkylated with an alkanesulfonic acid or an alkali haloalkylsufonate, or is
reacted with sodium sulfite or sodium bisulfite; or
f) a compound of the general formula (VII),

<IMG> (VII)
wherein R3, R4, R5, R7, R8, Rx, R, n, m, s and t each have the same meanings
as defined above and A4 is hydroxy, aralkoxy or substituted aralkoxy is
oxidized; or
g) if a compound of the general formula (I) containing a free
primary amino group and a free carboxy group is to be prepared, a compound
of the general formula (VIII),
<IMG> (VIII)
wherein R3, R4, R5, Rx, R, A4, B1, n, m, s and t each have the same
meanings as defined above, and R17 stands for halogen, nitro, arylazo,
substituted arylazo, hydrazo, monoarylhydrazo, diarylhydrazo, hydroxylamino,
or p-toluenesulfonyloxy, is reduced or reacted with ammonia; or
h) if a compound of the general formula (I) containing a free
primary amino group and a free carboxy group is to be prepared, a compound
of the general formula (IX),
<IMG> (IX)
wherein R, R4, R5, Rx, A4, B1, n, m, s and t each have the same meanings
46

as defined above, and R18 stands for oxyimino, imino, oxygen, or a group
of the general formula =N-NH-R20, wherein R20 stands for hydrogen or aryl,
is reduced, or is reacted with potassium cyanide and ammonia and subsequently
hydrogenated, or is reacted with .alpha.-methylbenzylamine and subsequently
hydrogenated; or
i) a compound of the general formula (X),
<IMG> (X)
wherein R, R4, R , Rx, B1, n, m, s and t each have the same meanings as
defined above, A5 stands for hydroxy, C1-4 alkoxy or p-methoxybenzyloxy,
A6 stands for hydroxy, C1-4 alkoxy or p-methoxybenzyloxy, and R19 stands
for hydrogen or a group of the general formula R15-OCO- (wherein R15 has
the same meanings as defined above), is decarboxylated by reacting it with
a hydrohalide, preferably with hydrogen bromide; or
j) a compound of the general formula (XI), (XII), (XIII) or (XIV)
(XI)
<IMG>
(XII)
<IMG>

<IMG> (XIII)
(XIV)
<IMG>
wherein R3, R4, R5, R, Rx, A4, B1, n, m, s and t each have the same meanings
as defined above, X1 stands for hydrogen or halogen, X2 stands for hydrogen
or halogen, but at least one of X1 and X2 is always halogen, R21 stands for
hydrogen, triphenylmethyl, benzyloxycarbonyl or substituted benzyloxycarbonyl,
R22 stands for nitro, arylazo, substitited arylazo, hydrazo, monoarylhydrazo,
diarylhydrazo or hydroxylamino, and R23 stands for hydrogen, halogen, C1-4
alkyl or hydroxy, is hydrogenated; or
k) if a compound of the general formula (I) containing a sulfonyl
group is to be prepared, a compound of the general formula (XV)
<IMG>
(XV)
48

wherein R4, R5, Rx, B1, n, m, s and t each have the same meanings as
defined above, R24 stands for hydrogen, C1-4 alkyl, aryl, substituted aryl,
aralkyl, acyl, arylsulfonyl, or a group of the general formula R15-OCO
(wherein R15 has the same meanings as defined above), and R25 stands for
hydrogen, C1-4 alkyl or aralkyl, is subjected to partial hydrolysis; or
1) a compound of the general formula (XVI),
<IMG>
(XVI)
wherein R4, R24, n and s each have the same meanings as defined above, is
reacted with a compound of the general formula
<IMG>
or a salt thereof, wherein R5, Rx, B1, m and t each have the same meanings
as defined above; or
m) a compound of the general formula (XVII),
(XVII)
<IMG>
wherein R, R5, Rx, B1, s, m,and t each have the same meanings as defined
above, and R26 stands for C1-4 alkyl, aryl or aralkyl, is subjected to
hydrogenation and partial hydrolysis; or
n) a compound of the general formula (XVIII)
49

<IMG>
(XVIII)
wherein R3, R4, R7, R8, A4, n and s each have the same meanings as defined
above, and A7 is hydroxy, azido, succinimidoxy, p-nitrophenoxy, pentachloro-
phenoxy, or C2-4 alkoxycarbonyloxy, is reacted with a compound of the general
formula (XIX)
<IMG> (XIX)
wherein R, R5, m and t and-RX each have the same meanings as defined above;
or
o) a compound of the general formula (XVIII), wherein R3, R4, R7,
R8, A4, A7, n and s each have the same meanings as defined above, is reacted
with a compound of the general formula (XX)
<IMG> (XX)
wherein R, R5, Rx, m and t each have the same meanings as defined above and
B3 is a group of the formula -SO2OH, -OSO2OH or -O-PO(OH)2; or
p) the protecting group attached to the .alpha.-amino group of a
compound of the general formula (XXI)
<IMG> (XXI)

wherein R3, R4 R5, R7, R8, Rx, R, A4, B1, m, n, s and t each have the same
meanings as defined above, is split off by acidolysis, hydrogenolysis, treat-
ment with dilute ammonium hydroxide, treatment with sodium, treatment with
sodium amide, treatment with hydrazine, or enzymatic hydrolysis; or
r) the protecting group attached to the .alpha.-carboxy group of a
compound of the general formula (XXI), wherein R3, R4, R5, R7, R8, Rx, R,
A4, B1, m, n, s and t each have the same meanings as defined above, is
split off by saponification, acidolysis, hydrogenolysis or enzymatic
hydrolysis; or
s) the .alpha.-amino group of a compound of the general formula (XXII),
<IMG> (XXII)
wherein R3, R4, R5, Rx, R, B1, m, n, s and t each have the same meanings as
defined above, is acylated; or
t) the .alpha.-carboxy group of a compound of the general formula (XXII),
wherein R3, R4, R5, Rx, B1, m, n, s and t each have the same meanings as
defined above, is esterified; or
u) if a polymeric or oligomeric derivative of the general
formula (XXIII)
<IMG> (XXIII)
51

wherein R1, R2, R3, R4, R5, RX, R, m, n, s and t each have the same
meanings as defined above, A8 stands for a group of the general formula
<IMG> (wherein R6, r and Y each have the same meanings as defined
above), and B4 is a mercapto group or a group of the formula -SO2OH,
-OSO2OH or -O-PO(OH)2, is to be prepared, an .alpha.-poly-amino-dicarboxylic acid-
.omega.-activated ester is reacted with cysteamine, taurine or homotaurine; or
v) a polymeric or oligomeric derivative of the general formula
(XXIII), wherein R1, R2, R3, R4, R5, x, R, m, n, s, t, A8 and R4 each have
the same meanings as defined above, is subjected to enzymatic hydrolysis pre-
ferably using carboxypeptidase or leucinaminopeptidase; or
x) if a compound of the general formula (XXIII) is to be prepared,
wherein R1, R2, R3, R4, R5, Rx, R, m, n, s, t, A8 and B4 each have the same
meanings as defined above, an .omega.-activated derivative of a peptide containing
an .alpha.-amino-dicarboxylic acid is reacted with a compound of the general
formula (XX), wherein R, R5, Rx, B3, m and t each have the same meanings as
defined above; or
y) glutathione is subjected to partial hydrolysis, partial
decarboxylation and oxidation; and, if required, converting into its salt
or liberating from its salt any of the thus-obtained compounds, or preparing
any of the above compounds in optically active form by using optically
active reagents or by subjecting the obtained racemic product to resolution.
2. A process as claimed in claim 1, variant a) for the preparation
of a compound of the general formula (I) containing a free primary amino
group, in which the protecting group attached to the nitrogen atom of a
compound of the general formula (II) is removed by treatment with an anhy-
drous hydrohalide (preferably hydrogen bromide), treatment with trifluoro-
aceticacid, or by catalytic hydrogenation.
3. A process as claimed in variant b) of claim 1 for the preparation
of a compound containing a free carboxy group, in which a compound of the
general formula (III) is saponified with an alkali hydroxide preferably in
the presence of water, an alcohol and/or acetone, or is treated with an an-
52

hydrous hydrohalide (preferably hydrogen bromide) or with trifluoroacetic
acid, or is subjected to catalytic hydrogenation, or is subjected to enzymatic
hydrolysis using leucineaminopeptidase.
4. A process as claimed in variant c) of claim 1 for the preparation
of a compound containing a free primary amino group and a free carboxy
group, in which the protecting groups of a compound of the general formula
(IV) are split off by treatment with hydrogen bromide in glacial acetic acid,
treatment with an alcohol containing dissolved dry hydrochloric acid, treat-
ment with trifluoroacetic acid, treatment with leucineaminopeptidase, or by
catalytic hydrogenation.
5. A process as claimed in variant d) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (V) is reacted with performic acid or with a mixture of glacial
acetic acid and hydrogen peroxide, or is heated in the presence of an
aqueous solution of an alkali sulfite.
6. A process as claimed in variant e) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (VI) is reacted with an alkali metal salt of a bromoethanesulfonic
acid or a bromopropanesulfonic acid.
7. A process as claimed in variant f) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (VII) is reacted with a mixture of glacial acetic acid and 30%
hydrogen peroxide.
8. A process as claimed in variant g) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the
general formula (VIII) is subjected to catalytic hydrogenation or is reduced
by electrolysis.
9. A process as claimed in variant h) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the
general formula (IX) is subjected to catalytic hydrogenation or is reduced
53

by electrolysis.
10. A process as claimed in variant i) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (X) is reacted with 48% hydrobromic acid.
11. A process as claimed in variant j) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (XI), (XII), (XIII) or (XIV) is subjected to catalytic hydrogenation
or is reduced by electrolysis.
12. A process as claimed in variant k) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (XV) is subjected to partial hydrolysis by treatment with a dilute
sodium hydroxide or sodium carbonate solution.
13. A process as claimed in variant 1) of claim 1 for the preparation
of a compound of the general formula (I), in which a compound of the general
formula (XVI), preferably pyroglutaminic acid, is reacted with taurine or
homotaurine.
14. A process as claimed in variant m) of claim 1, in which a compound
of the general formula (XVII) is subjected to catalytic hydrogenation and
then hydrolyzed in a glacial acetic acid medium below 40°C, or is heated in
the presence of red phosphorous, hydrogen iodide and glacial acetic acid
to split off the oxazolone ring and to saturate the double bond.
15. A process as claimed in claim 4 for the preparation of gamma-L-
glutamyl-taurine, in which N-carbobenzyloxy-gamma-(.alpha.-benzyl)-L-glutamyl-
taurine is subjected to catalytic hydrogenation preferably in the presence
of a palladium-on-carbon catalyst.
16. A process as claimed in claim 3 for the preparation of gamma-L-
glutamyl-taurine, in which gamma-(.alpha.-benzyl)-L-glutamyl-taurine is saponfied
in an aqueous potassium hydroxide solution.
17. A process as claimed in any of claims 1 to 16 for the preparation
of a salt, in which a compound of the general formula (I) is reacted with
54

an alkali metal or alkaline earth metal hydroxide or carbonate, or with an
organic base.
18. A process as claimed in variant n) of claim 1, in which a compound
of the general formula (XVIII), preferably a N-carbobenzyloxy-aminodicarboxy-
lic acid-.alpha.-benzyl- .omega.-p-nitrophenyl ester is reacted with cystamine in the
presence of aqueous pyridine, or a compound of the general formula (XVIII),
preferably a N-carbobenzyloxy-aminodicarboxylic acid-.alpha.-benzyl-ester is
reacted in the form of its mixed anhydride with cystamine.
19. A process as claimed in variant o) of claim 1, in which a compound
of the general formula (XVIII), preferably a N-carbobenzyloxy-aminodicarboxy-
lic acid-.alpha.-benzyl-.omega.-p-nitrophenyl ester is reacted with a compound of the
general formula (XX), preferably with taurine, N-methyl-taurine, homo-
taurine, cholamine phosphate or cystaminic acid, in the presence of aqueous
pyridine.
20. A process as claimed in variant p) of claim 1, in which the car-
bobenzyloxy group of a compound of the general formula (XXI), preferably of
a N-carbobenzyloxy-.alpha.-benzylester derivative, is split off by treatment with
hydrogen bromide in glacial acetic acid.
21. A process as claimed in variant r) of claim 1, in which the ester
group of a compound of the general formula (XXI), preferably of a N-carbo-
benzyloxy-.alpha.-benzylester derivative, is split off by saponification.
22. A process as claimed in variant s) of claim 1, in which a compound
of the general formula (XXII), preferably gamma-L-glutamyl-taurine, is
subjected to acetylation or benzoylation.
23. A process as claimed in variant t) of claim 1, in which a compound
of the general formula (XXII), preferably gamma-L-glutamyl-taurine, is
esterified with an alkanol, preferably methanol or ethanol in the presence
of hydrochloric acid.

Description

105180Z
lhis invention relates to novel amino acid derivatives and
pharmaceutical compositions containing the same, as well as to a process
for the preparation thereof.
The novel compounds according to the invention correspond to the
general formula ~I)
Rl R3
N - C - Co - Al
R (R4 IH) (I)
(ICH2) S
C0 - N - (CH)m - (CH)t - B
R R5 Rx
wherein Al stands for hydroxy, Cl 4 alkoxy, cycloalkoxy,
aralkoxy, substituted aralkoxy, aryloxy, substituted aryloxy or a group of
the general formulae -NR24 or -(~H-IC -CO)r~Y wherein R14 is hydrogen,
Cl 4 alkyl or aralkyl, R6 is hydrogen, Cl 5 alkyl, aralkyl, hydroxy-
substituted aralkyl, heteroaralkyl or a group of the general formula
-(CH)n-(CH2)s-CO-N-(CH)m-(C~)t-Bl, Y is hydroxy, amino, alkylamino, di-
R R R5 Rx
alkylamino, Cl 4 alkoxy or aralkoxy, and r is an integer of from 1 to 10
or an average polymerization grade of up to 2000, Bl is a group of the
formulae -S020H, -OS020H, -0-PO~OH)2 or -S-S-Rll, wherein Rll is Cl 4
alkyl, aralkyl or aryl or a residue obtained when removing group Bl from
the general formula (I), R stands for hydrogen, Cl 4 alkyl or aralkyl,
Rx stands for hydrogen or halogen, Rl stands for hydrogen, Cl 4 alkyl,
aryl, aryl having a nitro or alkoxy substituent, aralkyl, substituted
aralkyl, alkoxycarbonyl, aralkoxycarbonyl, aralkoxycarbonyl having a
halogen, alkoxy, nitro, phenylazo or alkoxyphenylazo substituent, alkyl-
substituted aryloxycarbonyl, acyl, benzoyl, arylsulfonyl or -(NH-CH-CO)p
group (wherein R6 has the same meanings as defined above and p is an integer
of from 1 to 10 or an average polymerization grade of up to 2000), or a
-C0- group, R stands for hydrogen, Cl 4 alkyl, aralkyl or a -C0- group,
but if Rl and R2 each stand for a -C0- group, they form a ring through
-- 1 --

105180Z
an O-phenylene, alkylene or -CH=CH- group, R3 stands for hydrogen,
carboxy or carbalkoxy, R4 stands for hydrogen, halogen, Cl 4 alkyl or
hydroxy, R5 stands for hydrogen, halogen, Cl 4 alkyl, carboxy, carboxamido,
carbalkoxy or carboaralkoxy, m is 1, 2 or 3, n is 1, 2, 3 or 4, s is 0, 1,
2, 3 or 4, and t is 1, 2 or 3.
The salts and optically active isomers of the above compounds
are also included by the scope of the invention.
Certain novel compounds according to the invention possess
valuable pharmaceutical properties, whereas other representatives can be
used as intermediates in the production of compounds with valuable physiolo-
gical or pharmaceutical properties.
Concerning its biological activities, an outstandingly
advantagious representative of the new compounds according to the invention
is gamma-L-glutamyl-taurine of the formula
H2N - CH - COOH
CH2
2 (XXIV
CO - NH - CH2 - CH2 - S020H
This compound possesses wide therapeutical and preventive effects
on pathological alterations connected directly or indirectly with the
injuries of the "AGAS" ~Aerobiospherical-Genetical-Adaptational-System).
To elucidate the notion of the AGAS, the most important tissues
and organs which constitute the system will b~ enumerated.
a) Biological interfaces forming the boundary between the
organism and the atmosphere as biosphere (skin and other dermal structures,
cornea and conjuctiva, mouth and pharyngeal cavity, respiratory tract and
lungs);
b) the skeletal system and the extremities (tubular and
spongious bones, ball joints, the synovial membrane, skeletal musculature);
c) the organs participating in the regulation of terrestrial ion
balance (the transepithelial transport system, intestinal villi and renal

105180Z
tubules);
d) the required thekodont teeth for the disintegration of solid
food (with tooth bed and fixed by the root);
e~ terrestrial hearing, smelling and sound-forming organs.
The compounds prepared according to the present invention exert
a biologically favourable therapeutic influence on the organs of the above
system, as well as on the tissues thereof.
Furthermore, still in connection with the AGAS system, the
compounds according to the invention exert the following effects:
Radioprotective effect, effect promoting wound healing, general
mensenshyma activation effect, protection against the increased danger of
the infections and contaminations of the mucous membrane and skin ~the
lysozyme production of the wet mucous membrane, development of ciliated
epithelium in the respiratory tract, etc.), increased protection against
the viral and fungal infections of the skin.
Against the significantly increased stress effects of terrestrial
life (e.g. meteorological and vigorous diurnal alterations, increased
danger of injury) the compounds tend to stabilize the adaptational syndrome,
by preventing simultaneously damages in the peripheral tissue caused
by glucocorticoids ~e.g. damages in the connective tissues, in the bone
matrix, etc.).
The development of immunohomeostasis (the increased recognition
of the self and non-self cells).
The compounds according to the invention exert their activities
in part directly, and in part through the control of the vitamin A metabolism,
by the production of more polar vitamin A metabolites. This activity
is similar to that exerted by parathormone on the 25-hydroxy-cholecalciferol-
1- a -hydroxylase enzyme of the renal tubules. The above facts explain
the wide and diverse biochemical, pharmacological and therapeutical activities
3 0 of the compounds according to the invention.
A) Effects of vitamin A character:
a) Pharmacological and biochemical effects;

10~180Z
Effect promoting the incorporation of labelled sulfate in
the cartilage of rats, and in the eye lens, the liver and lung tissues
of chicken embryo; effect promoting the incorporation of labelled phosphorous
in the cartilage of rats; effect promoting the synthesis o chondroitidin-
sulfate; effect favourably influencing wound healing, even decreased
wound healing caused by cortisone administration in rats and dogs; effect
increasing mastocyte degranulation; vitamin A potentiating effect in
the case of experimental hypo- or hypervitaminosis on rats and chickens;
moderation effect on the stress ulcer on rats; effect increasing lysosyme
production; effect influencing the trace element turnover (silicon, copper,
zinc, manganese, fluorine); effect promoting the epithel formation; effect
increasing the alkaline phosphatase activity; effect exerted on the formation
of pouch induced by the local effect of vitamin A; a very flat run of
the dose-response curve, and a change in premonitory sign for high doses;
effect activating the Golgi apparatus; effect promoting the formation
of goblet cells; effect increasing the concentration of serum vitamin A.
b) Use in the clinical therapy:
Keratoconjunctivitis sicca; Sjorgen's syndrome; rhino-laryngo-
pharingitis sicca; ozaena; bronchitis chronica; synobronchitis; mucovisciodis;
inclination of pheumopathies of the childhood; paradontosis; increased
disposition of the skin and the nucous membrane to infections of viral
and fungal origin; cortison-antagonism; operation wounds and injuries
of the mucous membrane; erosio coli; pruritis group; disturbances of
the taste and smell senses.
B) Effects ofn vitamin-A character:
a) Pharmacological and biochemical effects:
Transitory blood-sugar decreasing effect; effect increasing
phosphaturia and decreasing serum phosphate level; radiopro*ective effect;
in labyrinth tests at inactive animals a promoting effect on reaching
the target; effect moderating experimental fluoro is and cadmium intoxication;
effect decreasing the experimental lathyrism symptoms; effect lncreasing
the cyclic adenosine-monophosphate excretion of the kidney; effect increasing
-- 4 --

~OS180Z
enzyme activity of the liver tyrosine-aminotransferase.
b) Use in the clinical therapy:
less serious irradiation injuries; vitiligo; muscle hypotony;
psychoenergetizing effect, effects favourably influencing the involutional,
gerontological states and the mnestic functions; cheloid disposition;
spondylosis ankylopoetica; diseases of the locomotive organs of detritional
origin; sclerotic fundus; amyloidosis; morphea; mastopathya fibrocystica.
The durations of the treatment with the compounds according
to the invention are widely different. Upon an oral dose of 5 ~g. of
the chemically pure active substance administered three times a day some
of the patients become symptom-free already after two weeks ~e.g. in
the case of rhino-laryngo-pharyngitis sicca), for the treatment of certain
diseases one to two months are needed (e.g. parodontosis, Sjogren's syndrome),
whereas in the case of other diseases treatment periods of three to six
months are required (e.g. spondylosis ankylopoetica).
The compounds according to the invention can be converted
into cosmetical or pharmaceutical compositions for use in the human or
veterinary therapy. These compositions may contain the compounds according
to the invention as the sole active ingredient or in combination with
otherbiologically active substances. The active agents according to
the invention are administered preferably three times a day in dosages
of 50 to 500 nanograms/kg. body w ~ ht.
One tablet contains 2 to 20 micrograms, preferably about 10
micrograms of the active ingredi~nt admixed with biologically inert carriers
(e.g. lactose, starch) and usual auxiliary substances (e.g. granulating
agents and lubricants, such as polyvinyl pyrrolidone, gelatine, talc,
magnesium stearate, ultrafine silica, etc.). Taking into consideration the
very low dose, to obtain an even dispersion of the active substance in the
tablet it is preferable to admix the active principle in the form of
solution with the tablet mass prior to granulation and to prepare a homo-
geneous mixture using a kneeding machine. The required very low effective
dosage permits to prepare the active principle at a large laboratory scale,

1051802
even for the production of several billions of tablets, at an acceptable
price. The active principle is stable and therefore the tablets can be
stored for long time. The active principle content of depot tablets or
spansuled capsules may be between 10 to 30 ~g.
Injectable preparations containing the active principle in
powder ampoules optionally in admixture with a biologically indifferent
water-soluble diluent contain preferably 5 to 10 ~g. of active principle
per ampoule. The parenteral application may be intramuscular, subcutaneous
or intravenous. The active principle in the given concentrations does not
irritate the tissues or vessel walls, and can be applied in the form of
infusion as well.
Suppositories can be prepared with an active principle content
of 2 to 20 ~ug., preferably 10 ~ug., using cocoa butter or any synthetic
wax or fat (e.g. Imhausen mass, GFR) applicable for this purpose.
Ointments for dermatological or cosmetic purposes prepared with
the usual hydrophilic or hydrophobic ointment bases ~e.g. cholesterol,
paraffine, glycerine, lanoline, linseed oil, etc.) may have an active
principle content of 0.1 to 1.0 ~ug./g.
Aerosol preparations may contain the active principle in a
concentration of 0.1 to 1.0 ~g~g.Perlingual tablets may have an active
principle content of about 10 ~ug. per tablet and a degradation time of
0.5 to 1 hour.
The polymers with high molecular weights having sustained effect
can also be prepared e.g. in the form of suspensions with an active principle
content of 1 to 5 ,ug./g. Similarly, injectable preparations with sustained
effect can be prepared from the polymers or from the salts of the compounds
according to the invention with organic bases of high molecular weights
~e.g. protamine, histone). These compositions may contain the active
principle in an amount of 10 to 20 ~ug. per ampoule.
The dermatological and cosmetic powders may have an active
principle content of 0.1 to 1 /ug./g., and contain the usual carriers
(e.g. talc).

~05180Z
Eye drops applied for ophthalmologic purposes and the ointments
miscible or immiscible with tear have an active principle content of
0.1 to 1.0 ~g./g.
For paediatric purposes the most preferred dosage is 0.3 ~ug.
of active principle per kg. of body weight.
All sterile compositions are prepared preferably by sterile
filtration.
Several combinations of the above preparations containing the
compounds according to the invention increase, supplement or modify the
desired preventive, therapeutical or cosmetic effect. Primarily, the
following combinative supplementary components should be mentioned:
Vitamin A, vitamin C, vitamin E, vitamin K, trace elements,
cortisone and its derivatives, progesterone, hormones of the thyroid gland,
products of radiomimetic and immunosuppressive effects, psychopharmacons
(especially tranquillizers or thymoleptics), organic silicon compounds,
gerontological preparations, oral antidiabetics, antiphlogistics
antihistamines, etc. The dosage of the components in the combination is
generally identical with the usual therapeutical dosages when using them
independently.
The compounds according to the invention can be applied
furthermore as additives in therapeutical and nutrient premixes. Used in
such compositions the compounds increase the weight gain and decrease the
vitamin A demand and/or increase the absorption and metabolism of vitamin A.
The compounds improve the absorption and increase the blood level of trace
elements. When used as feed additive, they can be administered to the
animals in a daily oral dosage of 100 to 300, preferably about 200 nanograms/
kg. body weight. This corresponds generally to a concentration of 1 to 2 ~g.
per kg. of feed (i.e. 1 to 2 mg./ton or 0.001 to 0.002 ppm) when admixed
with the animal feed. Considering the very low concentration required, the
compounds according to the invention can be admixed to vitamin premixes or
microcapsules containing other valuable feed additives, or can be administered
as an additive of the drinking water or the licking salt. The compounds
-- 7 --

~OS180Z
according to the invention can also be used for veterinary purposes in
forms similar to those applied in the human therapy (epithelization, wound
healing, bone fTactures, etc.).
It is a common structural characteristic of the compounds having
the general formula ~I) that they contain an ~-substituted dicarboxylic
acid moiety the ~-carboxy group of which is attached through an amido
bond to a primary or secondary amino group containing in the alkyl side chain,
beside other substituentsJ a strongly acidic group in the ~-position.
The compounds of the general formula ~I) or their salts or
optically active isomers can be prepared according to the invention as
follows:
a) if a compound of the general formula ~I) containing a
free primary amino group is to be prepared, the protecting group of a
compound of the general formula ~II)
R 13
N - C - COOH
R8 / (R4-CH)n (II)
(CH2) S
CO - N - (CH)m - (CH)t ~ B
R R5 Rx
wherein R3, R4, R5, RX, R, Bl, n, m, s and t each have the same meanings
as defined above and R7 stands for aralkyl, formyl, trifluoroacetyl, p-
toluene-sulfonyl or -CO- group or a group of the general formulae
R15-aCo- or H(NH-C,~I-CO)p, wherein p and R6 each have the same meanings
as defined above, and R15 is Cl 4 alkyl, cycloalkyl, aralkyl, substituted
aralkyl, aryl or substituted aryl, and R8 stands for hydrogen or -CO-, but
if R7 and R8 each stand for a -CO- group, they form a ring through an
o-phenylene, alkylene or -CH=CH- group, is split off by acidolysis,
hydrogenolysis, treatment with dilute ammonium hydroxide, treatment with
sodium, treatment with sodium amide, treatment with hydrazine, or enzymatic
hydrolysis preferably using leucineaminopeptidase; or
-- 8 --

105~80Z
b) if a compound of the general formula ~I) containing a free
carboxy group is to be prepared, a compound of the general formula (III),
,R3 CO A2
~R4-CH)n IIII)
~C,H2) S
CO - N - (CH)m - ~CH)t - B
R R5 Rx
wherein R, R3, R4, R5, RX, Bl, n, m, s, and t each have the same meanings
as defined above and A2 stands for a Cl 4 alkoxy, aralkoxy or substituted
aralkoxy group or a group of the general formulae -NR16 or -~NH-CH-CO)rY
(wherein R6, Y and r each have the same meanings as defined above, and
R16 is hydrogen, Cl 4 alkyl or aralkyl, is subjected to saponification,
acidolysis, hydrogenolysis or enzymatic hydrolysis; or
c) if a compound of the general formula ~I) containing a free
primary amino group and a free carboxy group is to be prepared, the
protecting groups attached ts the d-amino group and the ~-carboxy group
of a compound of the general formula ~IV),
R3
R9 - HN - C - CO - A3
(R4-CH)n
~C,H2)S (IV)
CO - N - ~CH)m - (CH)t ~ B
R R5 Rx
wherein R3, R4, R5, RX, R, Bl, n, m, s and t each have the same meanings as
defined above, R9 stands for aralkyl, formyl, p-toluenesulfonyl or a group
of the general formulae R15-oCo- or H(NH-CH-CO)p(wherein R 5, R6 and p each
R6
have the same meanings as defined above), and A3 stands for Cl 4 alkoxy,
aralkoxy, substituted aralkoxy, or an aralkoxy, -NR126 or -(NH-CH-CO)rY

lOS180;~
group attached to a solid polymer matrix, preferably to a styrene-di-
vinylbenzene copolymer (wherein R16, R6, R and Y each have the same meanings
as defined above), are split off simultaneously by acidolysis, alkaline
hydrolysis, hydrogenolysis, treatment with sodium, treatment with sodium
amide or enzymatic hydrolysis; or
d) if a compound of the general formula (I) containing sulfonyl,
- sulfonyloxy or phosphoryloxy group is to be prepared, a compound of the
general formula (V),
Rl R,3
2\ N - C - CO - Al
~R4-CH)n (~)
(CH2) 5
CO - N ~ (CH)m ~ (CH)t ~ B2
R R5 Rx
wherein Rl, R2, R3, R4, R5, RX, R, Al, n, m, s and t each have the same
meanings as defined above and B2 is halogen, hydroxy, p-toluenesulfonyloxy,
or a group of the formulae -SH, -SO-OH or -SO2R10, wherein R10 is Cl 4
alkoxy or aralkoxy, is oxidized, hydrolysed, reacted with an alkali sulfite
or alkali bisulfite, or is esterified with sulfuric acid or phosphoric
acid or with a derivative thereof; or
e) if a compound of the general formula ~I) containing a
sulfonyl group is to be prepared, a compound of the general formula (VI),
1 R3
R
R2
R -CH)
, n (VI)
CCH2) s R12
CO - N \ 13
wherein Rl, R2, R3, R4, Al, n and s each have the same meaningS as defined
20 above, R12 stands for hydrogen, Cl 4 alkyl, aralkyl, or -CH2-, and R13 stands
for alkali metal, vinyl group or -CH2- group, but when R12 and Rl3 each
represent -CH2- group, they form together an aziridine ring, is alkylated
- 10 -

105180Z
with an alkenesulfonic acid or an alkali haloalkylsulfonate, or is reacted
with sodium sulfite or sodium bisulfite; or
f) a compound of the general formula (VII),
R3
R7 N - C - CO - A4
R / ~R4-CH) (VII)
C,H2) s
CO - N - ~CH)m - ~CH)t - S
R R5 RX 2
wherein R3, R4, R5, R7, R8, RX, R, n, m, s and t each ha~e the same meanings
as defined above and A4 is hydroxy, aralkoxy ~preferably benzyloxy) or
substituted aralkoxy (preferably p-methoxybenzyloxy or p-nitrobenzyloxy),
is oxidized; or
g) if a compound of the general formula ~I) containing a free
primary amino group and a free ca~boxy group is to be prepared, a compound
of the general formula (V~II),
R,3
t
(R4-CH~n ~VIII)
(CH2 ) s
CO - N - (CH)m - (CH)t ~ B
R R5 Rx
wherein R3, R4, R5, RX, R, A4, Bl, n, m, s and t each have the same meanings
as defined above, and R17 stands for halogen, nitro, arylazo, substituted
arylazo, hydrazo, monoarylhydrazo, diarylhydrazo, hydroxylamino or p-
toluenesulfonyloxy, is reduced or reacted with ammonia; or
h) if a compound of the general formula ~I) containing a free
primary amino group and a free carboxy group is to be prepared, a compound
of the general formula (IX),

~OS180Z
R18 = C - CO - A4
(R4-CH)
, n ~IX)
(C,H2) s
CO - N ~ (CH)m ~ (CH)t ~ B
R R RX
wherein R, R4, R5, RX, A4, B , n, m, s and t each have the same meanings as
defined above, and R18 stands for oxyimino, imino, oxygen, or a group of the
general formula =N-NH-R20, wherein R20 stands for hydrogen or aryl, is
reduced, or is reacted with potassium cyanide and ammonia and subsequently
hydrogenated, or is reacted with ~-methylbenzylamine and subsequently
hydrogenated; or
i) a compound of the general formula (X),
CO - A6
Rl9 - NH - C - CO - A
(R4-CH)n (X)
(C,H2) s
, (, )m (, )t
R R5 RX
wherein R, R4, R5, RX, Bl, n, m, s and t each have the same meanings as
defined above, A5 stands for hydroxy, Cl 4 alkoxy or p-methoxybenzyloxy,
A6 stands for hydroxy, Cl 4 alkoxy or p-methoxybenzyloxy, and RlS stands
for hydrogen or a group of the general formula R15-oCo- (wherein R15 has
the same meanings as defined above), is decarboxylated by reacting it with
a hydrohalide, preferably with hydrogen bromide or
j) a compound of the general formula (XI), ~XII), (XIII) or (XIV)
R,3
R21 - NH - C - CO - A4
(XI)
CH-X2)
CO N, (C,H)m (, ) t
R R5 RX
- 12 -

1051802
R,3
R22 _ C - CO A4
, n (XII)
~CH-X2)
CO - N ~ (CH)m ~ (CH)t ~ B
R R5 Rx
R - HN - C - CO - A4
R - C
R23 C (XIII)
(C,H2) S
CO N ~C,H)m ~, )t
R R5 Rx
R3
R22 _ C - CO A4
R4 - C
R23 _ C (XIV)
(CH2) S
CO N (ClH)m (, )t
R R5 Rx
wherein R3, R4, R5, R, RX, A4, Bl, n, m, s and t each have the same meanings
as defined above, Xl stands for hydrogen or halogen,X2 stands for hydrogen
or halogen, but at least one of Xl and x2 is always halogen, R21 stands for
hydrogen, triphenylmethyl, benzyloxycarbonyl or substituted benzyloxycarbonyl,
R22 stands for nitro, arylazo, substituted arylazo, hydrazo, monoarylhydrazo,
diarylhydrazo or hydroxylamino, and R23 stands for hydrogen, halogen, Cl 4
0 alkyl or hydroxy, is hydrogenated; or
k) if a compound of the general formula (I) containing a sulfonyl
group is to be prepared, a compound of the general formula ~XV)

1051802
~ N ; CH ~ - ~CH)m - ~CH)t ~ Bl ~XV)
(R -CH)n /C=0
\(CH2) S
wherein R4, R5, RX, Bl, n, m, s and t each have the same meanings as defined
above, R24 stands for hydrogen, Cl 4 alkyl, aryl, substituted aryl, aralkyl,
acyl, arylsulfonyl, or a group of the general formula R15-oCo- (wherein R15
has the same meanings as defined above), and R25 stands for hydrogen,
Cl_4 alkyl or aralkyl, is subjected to partial hydrolysis, or
1) a compound of the general formula ~XVI),
R24 -/N CH - COOH
O=C \ ~ HC-R4)n (XVI)
~CH2) s
wherein R4, R24, n and s each have the same meanings as defined above, is
reacted with a compound of the general formula
H2N (C,H)m ~, )t
R5 RX
or a salt thereof, wherein R5, RX, Bl, m and t each have the same meanings
as defined above; or
m) a compound of the general formula ~XVII),
26
~C - O ~
C ~XVII)
CH
~C,H2) 5
CO - N - ~CH)m - (CH)t - B
R R5 Rx
wherein R, R5, RXl Bl, s, m and t each have the same meanings as defined

~05~80Z
above, and R26 stands for Cl 4 alkyl, aryl or aralkyl, is subjected to
hydrogenation and partial hydrolysis; or
n) a compound of the general formula ~XVIII),
7 R3
N - C - CO - A
R8 / (R4-CH)n (XVIII)
CH2 ) s
CO - A7
wherein R3, R4, R7, R8, A4, n and s each have the meanings as defined above
and A7 is hydroxy, azido, succinimidoxy, p-nitrophenoxy, pentachlorophenoxy,
or C2 4 alkoxycarbonyloxy, is reacted with a compound of the general
formula (XIX)
~ HN - (CH) - ~CH)t - S ~ ~XIX)
0 wherein R, R5, m and t each have the same meansings as defined above; or
o) a compound of the general formula ~XVIII), wherein R3, R4,
R7, R8, A4, A7, n and s each have the same meanings as defined above, is
reacted with a compound of the general formula ~XX),
HN - (CH)m - (CH)t - B (XX)
R R Rx
wherein R, R5, RX, m and t each have the same meanings as defined above and
B3 is a group of the formula -S020H, -OS020H or -O-PO(OH)2; or
p) the protecting group attached to the ~-amino group of a
compound of the general formula (XXI)
R7 R3
R8 N - C - CO - A4
(R -CH)n (XXI)
(CH2)
CO - N ~ ~CH)m ~ ~CH)t ~ B
R R Rx

~OSl~OZ
wherein R3, R4, RS, R7, R8, RX, R, ~4, Bl, m, n, s and t each have the same
meanings as defined aboYe, is split off by acidolysis, hydrogenolysis,
treatment with dilute ammonium hydroxide, treatment with sodium, treatment
with sodium amide, treatment with hydrazine, or enzymatic hydrolysis; or
r) the protecting group attached to the ~-carboxy group of a
compound of the general formula (XXI), wherein R3, R4, R5, R7, R8, RX, R,
A4, Bl, m, n, s and t each have the same meanings as defined above, is
split off by saponification, acidolysis, hydrogenalysis or enzymatic
hydrolysis; or
s) the a-amino group of a compound of the general formula (XXII),
RI3
H2N - C - COOH
(R4 -CH)n
I (XXII)
(C,H2) S
CO N, (C,H)m (, )t
R R5 RX
wherein R3J R4, R5J RXJ RJ B1J mJ n, s and t each have the same meanings
as defined aboveJ is acylated; or
t) the ~-carboxy group of a compound of the general formula
(XXII)J wherein R3, R4, R5, RXJ B1, m, nJ s and t each have the same
meanings as defined aboveJ is esterified; or
u) if a polymeric or oligomeric derivative of the general formula
~XXIII)
R3
R N - C - CO - A8
R2 (R4-CH)n (XXIII)
(CH2) 5
CO - N - (CH)m ~ (CH)t - B
R R5 RX
wherein R1J R2J R3J R4, R5, RX, R, m, nJ s and t each have the same meanings
as defined above, A8 stands for a group of the general formula -(NH-CH-CO)rY
- 16 -

1051802
~wherein R6, r and Y each have the same meanings as defined above), and B4
is mercapto group or a group of the formula -SO20H, -OSO2OH or -O-PO(OH)2,
is to be prepared, an -poly-amino-dicarboxylic acid-~ -activated ester is
reacted with cysteamine, taurine or homotaurine; or
v) a polymeric or oligomeric derivative of the general formula
(XXIII), wherein Rl, R2, R3, R4, R5, RX, RJ m, nJ sJ tJ A8 and R4 each
have the same meanings as defined aboveJ is subjected to enzymatic hydrolysis
perferably using carboxypeptidase or leucinaminopeptidaseJ optionally after
the prior oxidation of the mercapto group; or
x) if a compound of the general formula ~XXIII) is to be
h i Rl R2 R3 R4, R5, RX, R, mJ nJ SJ t, A
have the same meanings as defined above, an ~ractivated derivative of a
peptide containing an -aminodicarboxylic acid is reacted with a compound of
the general formula ~XX), wherein RJ R5, RXJ B3, m and t each have the same
meanings as defined above; or
y) glutathione is subjected to partial hydrolysis, partial
decarboxylation and oxidationJ optionally after the previous protection of
the -amino and -carboxy groups of the glutaminic acid moiety; and, if
desired, any of the thus-obtained compounds is converted into its salt or
is liberated from its salt, and/or any of the above compounds is prepared
in optically active form by using optically active reagents or by subjecting
the obtained racemic product to resolution.
According to process variant o) of the invention the compounds
of the general formula (I) are prepared by forming an acid amide bond. In
this case the appropriate -amino-dicarboxylic acid derivativeJ with a
protecting group or another substituent on the -amino group and optionally
also on the -carboxy group, is coupled through the ~-carboxy group with
e.g. 2-amino-ethanesulfonic acid, 3-amino-propanesulfonic acid, 2-phospho-
ethanolamine, 3-phospho-propanolamine or cysteinic acid. In this reaction
a wide choice of protecting groups can be applied. The most preferred
method of coupling is the "active ester" method. The formation and selective
removal of the protecting groups, as well as the methods of coupling are

105180Z
described in detail by E. Schroder and K. L'ubke C"The Peptides" Yol. 1:
Methods of Peptide Synthesis, Academic Press, 1965).
Process variant n) of the invention can be performed e.g. by
acylating the amino group of cystamine or a substituted cystamine derivative
with an -amino-dicarboxylic acid derivative. Several coupling methods, such
as the "active ester" or "mixed anhydride" methods can be used to perform
the acylation. The product of this coupling reaction is reacted with
hydrogen peroxide or a peracid, to yield the appropriate compound of the
general formula (I) via the oxidative splitting of the disulfide bond (see
process variant f/ of the invention).
According to process variant d) of the invention an ~-amide of
an a-amino-dicarboxylic acid is prepared first, wherein the ~-amine component
contains another group in the place of the strongly acidic functional group.
This latter group may be e.g. a sulfhydryl or sulfinic acid group. These
compounds can be converted to the desired end-products by oxidation. If
the functional group is halogen or p-toluene-sulfonyloxy group (J. Chem. Soc.
1964, 824), these compounds can be reac~ed with an alkali sulfite or alkali
bisulfite to yield compounds of the general formula (I) that contain sulfo
groups. The intermediates containing hydroxy groups can be esterified to
yield compounds of the general formula ~I) that contain hydrosulfate or di-
hydrophosphate groups. If the intermediate contains a sulfonic ester group,
this compound can be converted to the desired end-product of the general
formula (I) by mild partial hydrolysis.
One can also use glutamine, asparagine or a sub5tituted derivative
thereof as starting material, the substituent being attached to a position
other than the acid amide moiety. In this instance, according to process
variant e) of the invention, one of the acidic hydrogens of the acid amide
group is replaced with e.g. metallic sodium, and the obtained compound is
reacted with 2-bromo-ethanesulfonic acid or a salt thereof or with an
alkanesulfonic acid to yield the respective compound of the general formula
3o (I). As starting substances the ~-vinylamides or the w-aziridine derivatives
of the appropriate a-aminodicarboxylic acids can be used as well. Both of

105~80Z
them can be reacted with an alkali sulfite or alkali bisulfite to yield
the end-products of the general formula (I).
According to process variants g) and h) of the invention, an
~-amide of an a-substituted dicarboxylic acid, wherein the substituent in
the ~-position is other than amino, is reacted to introduce an amino group
into the -position. As starting substances, e.g. the ~-nitro-, a-arylazo-,
a-hydrazo, a-arylhydrazo-, a-hydroxylamino-, ~-oxyimino- or a-imino-
dicarbo~ylic acid-~-amides or the ~-amides of the a-ketodicarboxylic acid
hydrazones can be used. Starting from these compounds, the end-products of
the general formula (I)can be obtained by reduction, preferably by catalytic
hydrogenation. If the ~-amide of an a halo- or a-p-toluenesulfonyloxy-
dicarboxylic acid is used as starting substance, the aimed ~-amino compounds
can be obtained by reacting the starting substances with ammonia. Various
methods can be utilized to convert a-keto-dicarboxylic acid-~-amides into
a-amino-dicarboxylic acid amides. The keto group can be converted into
amino group e.g. by reacting the keto compound with potassium cyanide in
the presence of ammonium hydroxide, and hydrogenating the obtained intermediate
in the presence of cobalt chloride (Bull. Chem. Soc. Japan 36, 763 /1963/).
If the a-ketocarboxylic acid derivative is condensed with optically active
a-methyl-benzylamine, and the intermediate is hydrogenated, the aimed
a-amino compound is obtained in optically active form (J. Am. Chem. Soc.
83, 4798 /1961/).
Process variant i) of the invention proceeds via an intermediate
prepared by a malonester synthesis. The removal of the ester groups and
the partial decarboxylation can be performed in a single step by admixing
the intermediate with 48% hydrobromic acid and allowing the mixture to stand
for one day or heating it gently for several hours.
If a compound containing a halogen atom or a double bond in the
side chain of the a_aminodicarboxylic acid moiety is used as starting sub-
stance or intermediate, the compounds of the general formula (I) can be
prepared by hydrogenation (see process variant j/ of the invention). One can
also use such compounds that contain a halogen atom or a double bond in the
- 19 -

105180Z
side chain of an -substituted dicarboxylic acid moiety which can be
converted by hydrogenation into -aminodicarboxylic acid (see process variants
g/ and h/ of the invention).
According to process variant k) of the invention an ~-amino-
glutarimide or a-amino-succinimide is converted first into its alkali metal
salt, and subsequently the imino nitrogen is alkylated. As alkylating agent
e.g. 2-bromo-ethane-sulfonic acid or 3-bromo-propanesulfonic acid can be
used. The obtained N-sulfoethyl or N-sulfopropyl derivative is then sub-
jected to partial hydrolysis in a slightly alkaline medium. In this reaction
the cyclic intermediate converts primarily into the respective ~-amide,
which can be separated from the small amount of -amide by ion exchange
chromatography.
Process variant 1) of the invention also leads to compounds of
the general formula (I). When reacting 5-carboxy-pyrrolid-1-one ("pyroglut-
aminic acid") or 6-carboxy-piperid-1-one e.g. with taurine, homotaurine,
N-methyl-taurine etc., or with another amine containing a strongly acidic
functional group, or with an alkali metal or tertiary base salt of these
compounds, the lactam ring splits and ~-amides are formed.
According to process variant m) of the invention, the ~-amides
are prepared via azlactone type intermediates. The saturation of the
double bond of the molecule and the removal of the oxazolone ring can
be performed by hydrogenation and subsequent partial hydrolysis. As
another method, the compound can be heated in a glacial acetic acid medium
in the presence of red phosphorous and hydrogen iodide.
The substituted derivatives of the compounds having the general
formula (I) can be prepared by various methods. One of these methods
is to remove one of the protecting groups of an intermediate containing
protecting groups on both the -amino and the -carboxy groups. According
to process variant p) of the invention, only the amino-protecting group
is removed. In this case one must apply a selective method. Thus, for
example, a mixture of glacial acetic acid and hydrobromic acid can be
used to advantage for N-carbobenzyloxy-~-benzyl ester derivatives. Process
- 20 -

~05180Z
variant T) of the invention is particularly suitable for the selective
splitting of the -ester group, e.g. by alkaline saponification.
Partially substituted derivatives can also be prepared from the
compounds of the general formula (I) containing free amino and free u-
carboxy groups. Process variant s) of the invention yields acyl derivatives,
whereas process variant t) of the invention yields the esterified analogues
by simple, well-known methods. Thus, for example, acetyl, benzoyl or
p-toluenesulfonyl derivatives can be prepared, or the compounds containing
free carboxy groups can be esterified, preferably in the presence of gaseous
hydrochloric acid, with an alcohol to obtain e.g. Cl 4 alkyl esters, aryl
esters, aralkyl esters, etc.
According to process variant x) of the invention a peptide
containing an a-amino-dicarboxylic acid moiety ~e.g. a-glutamyl-glycine) is
activated on its ~carboxy group (e.g.converted into its p-nitrophenyl
ester), and this compound is used to acylate taurine, homotaurine or
cholamine phosphate.
Finally, the oligomeric or polymeric derivatives of the compounds
having the general formula CI) can also be prepared according to the invention.
Thus, according to process variant u), an a-poly-aminodicarboxylic acid-
-Cactivated) ester, such as a-poly-L-glutaminic acid-~-p-nitrophenyl ester
is reacted with taurine, homotaurine or cysteamine to obtain the desired
compounds (when using cysteamine an oxydation step should also be inserted).
If desired, these polymers can be decomposed into the monomeric substances
of the general formula (I) using the method of process variant v). The
decomposition can be performed by enzymatic hydrolysis using e.g. carboxy-
peptidase or leucinaminopeptidase.
The invention is elucidated in detail by the aid of the following
non-limiting Examples.
Example 1
40.85 g. (0.11 moles) of carbobenzyloxy-L-glutaminic acid- a-
benzyl ester (Liebig's Ann. 655, 200 /1962/) are dissolved in 500 ml. of
acetonitrile. The solution is cooled t~ -15C under exclusion of air

105180Z
humidity, and 15.4 ml. ~0.11 moles) of triethylamine are added to the stirred
mixture followed by 15,4 ml. (0.11 moles) of isobutyl chloroformate. The
mixture is stirred at -15C for 40 minutes, thereafter 28 ml. (0.2 moles)
of triethylamine, 11.26 g. (0.05 moles) of cystamine dihydrochloride, and
finally 250 ml. of acetonitrile are added. The mixture is stirred
vigorously at -15C for 2 hours and then at room temperature for 4 hours.
The reaction mixture is evaporated in vacuo at 30C. The residue
is admixed with 200 ml. of ice-cold water under cooling and stirring, and the
obtained mixture is evaporated in vacuo at 35C. 250 ml. of water and 500
ml. of ethyl acetate are added to the residue, and the mixture is poured
into a separation funnel. The ethyl acetate phase is washed successively
with 250 ml. of water, 2x250 ml. of 5% aqueous sodium carbonate solution,
2x250 ml. of 1 n hydrochloric acid and 250 ml. of water. (The aqueous-
alkaline wash can be acidified with hydrochloric acid and extracted with
ether to obtain about 5 g. of non-reacted carbobenzyloxy-L-glutaminic
acid- a-benzyl ester.) The ethyl acetate solution is dried over anhydrous
sodium sulfate, and evaporated to dryness in vacuo at 30C. A thick,
oily residue is obtained which crystallizes upon standing. The residue is
triturated with 250 ml. of absolute ether, the crystalline substance is
filtered off, and the thus-obtained crude product, weighing about 40 to
42 g., is recrystallized from 100 ml. of ethyl acetate and 170 ml. of
ether. 29.3 g. of N,N'-bis-(N-carbobenzyloxy-gamma-/ ~-benzyl/-L-glutamyl)-
cystamine are obtained, m.p.: 91-92C.
Analysis:
Calculated for C44H50N4010S2 (
C: 61.52 % H: 5.89 % N: 6.52 % S: 7.46 %
Found: C; 60.85 % H: 5.91 % N: 6.61 % S: 7.72 %
Example 2
25.77 g. (0.03 moles) of N,N'-bis-(N-carbobenzyloxy-gamma-/ ~-
benzyl/-L-glutamyl)-cystamine (prepared as described in Example 1) are
dissolved in 75 ml. of glacial acetic acid. The solution is cooled in an
ice bath and a freshly prepared mixture of 75 ml. 30% hydrogen peroxide

1051802
and 225 ml. of glacial acetic acid is added dropwise within 15 minutes.
Thereafter the ice bath is removed, the mixture is stirred at ~oom
temperature for 4 hours, and evaporated in vacuo at 30C. the oily product
is dried in a desiccator first over phosphorous pentoxide and then over
solid potassium hydroxide. 28.5 g. of carbobenzyloxy-gamma-( -benzyl)-L-
glutamyl-taurine are obtained. This crude product can be used without
purification in the preparation of gamma-L-glutamyl-taurine.
Example 3
26.32 g. (55mmoles) of carbobenzyloxy-gamma-( -benzyl)-L-
glutamyl-taurine ~prepared as described in Example 2) are dissolved in
50 ml. of glacial acetic acid, and 50 ml. of glacial acetic acid containing
4 moles of hydrogen bromide are added. A vigorous carbon dioxide development
sets in. The mixture is allowed to stand at room temperature for 2 hours,
and then eYaporated in vacuo at 30C. The oily residue is dissolved in
170 ml. of water, and the solution is washed with 5x70 ml. of etheT. The
aqueous phase is evaporated in vacuo at 35C. 20.42 g. of gamma-~ -benzyl)-
L-glutamyl-taurine are obtained. The product can be recrystallized from
90% aqueous ethanol. Rf = 0.53 ~in a 15:10:3:12 mixture of n-butanol,
pyridine, glacial acetic acid and water); 0.39 (in a 4:1:1 mixture of n-
butanol, glacial acetic acid and water).
Example 4
529 mg. (1.1 mmoles) of carbobenzyloxy-gamma-~ -benzyl) L-
glutamyl-taurine (prepared as described in Example 2) are dissolved in
5 ml. of 1 N aqueous potassium hydroxide solution, and the mixture is
allowed to stand at room temperature for 4 hours. The solution is washed
with 3x3 ml. of ether, passed through a 1 cm. x 20 cm. column filled with
Dowex* 50x2 resin, and the column is eluted with water. 50 ml. of eluate
are collected and evaporated to dryness in vacuo at 35C. The obtained
crude carbobenzyloxy-gamma-L-glutamyl-taurine is purified by paper
electrophoresis at pH 6.5. Relative motility ~related to cysteinic acid):
1.05. Rf = 0.57 ~in a 15:10:3:12 mixture of n-butanol, pyridine, glacial
acetic acid and water).
* Trade ~ark - 23 -

105180Z
Example 5
5.79 g. ~12.1 mmoles) of carbobenzyloxy-gamma-( ~-benzyl)-L-
glutamyl-taurine (prepared as described in Example 2) are dissolved in a
mix~ure of 100 ml. of ethanol and 25 ml. of water. 0.5 g. of 10% palladium-
on-carbon catalyst are added, and the mixture is hydrogenated under shaking.
It is advantageous to add two further portions of the catalyst (0.25 g each)
to the mixture during the reaction. When the hydrogen uptake ceases the
catalyst is filtered off, the filtrate is evaporated in vacuo at 30C, and
the oily residue is dried in a desiccator over phosphorous pentoxide. 3.1 g
of gamma-L-glutamyl-taurine are obtained. The product is highly water-
soluble, but is insoluble in alcohol. It can be crystallized by dissolving
it in a minimum amount of water and adding alcohol to the solution in small
portions. The crude crystalline substance melts at 202-204C.
The product is recrystallized several times from 80% ethanol.
2 02 g, (66 %, calculated for the starting N,N'-bis-/N-carbobenzyloxy-
gamma-( ~-benzyl)-L-glutamyl/-cystamine~ of the purified product are
obtained; m.p.: 219-220C; ( )20 = +14 (water, c = 1.02).
Relative motility values in paper electrophoresis (related to
cysteinic acid): 0.73 at pH 6.5, and 0.53 at pH 1.8. Rf = 0.19 (in a
20 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic acid and water).
Analysis:
Calculated for C7H14N206S (M = 254-27)
C: 33:07% H: 5.55% N: 11.02% O: 37.75% S: 12.61%
Found C: 33.15% H: 5.76% N: 10.94% 0: 37.53% S: 12.17%
Example 6
20.42 g. of gamma-( ~-benzyl)-L-glutamyl-taurine (prepared as
described in Example 3) are dissolved in 150 ml. of 1 N aqueous potassium
hydroxide solution. The mixture is allowed to stand at room temperature
for 4 hours, then it is poured onto a 2 cm. x 100 cm. column filled with
3o Dowex 50x2 resin (Fluka, 100-200 mesh, H cycle), and the column is eluted
with water. 300 ml. of eluateare collected from the start of the washing
step, and this eluate is evaporated in vacuo at 35C. The oily residue is
_ 24 -

11D5180Z
crystallized by adding 8-10 ml. of water and about 100 ml. of ethanol.
The crystals are filtered off, washed with alcohol, and dried. 13.7 g.
of gamma-L-glutamyl-taurine are obtained. The product is recrystallized
from 80% aqueous ethanol. 9.79 g. ~70 %, calculated for N,N'-bis-(N-
carbobenzyloxy-gamma-/ ~benzyl/-L-glutamyl)-cystamine) of the purified
product are obtained.
Example 7
5.42 g. (11 mmoles) of carbobenzyloxy-L-glutaminic acid~
benzyl)-gamma-p-nitrophenylester (Chem. Ber. 96, 204 /1963/) are dissolved
in 50 ml. of pyridine. The solution is cooled to 0C, and a solution of
1.25 g. (10 mmoles) of taurine in 20 ml. of water is added dropwise within
30 minutes under vigorous stirring. Thereafter 3.08 ml. (22 mmoles) of
triethylamine are added dropwise to the mixture, and cooling and stirring
are discontinued. The mixture is left to stand at room temperature for 72
hours and then evaporated in vacuo. The residue is dissolved in 50 ml.
of water, and 1 n hydrochloric acid is added to the solution until the
disappearance of the yellow colour. The solution is washed with lOx50 ml.
of ether in order to remove p-nitrophenol, and the aqueous phase is
evaporated in vacuo. 6.9 g. of carbobenzyloxy-gamma-(~ -benzyl)-L-glutamyl-
taurine triethylammonium salt are obtained.
This compound is subjected to catalytic hydrogenation as described
in Example 5, thereafter the solvent is evaporated in vacuo, the residue is
dissolved in a minimum amount of water, and the solution is poured onto a
2 x 40 cm. column filled with Dowex 50x2 resin. The resin eolumn is eluted
with water. About 120 ml. of eluate are collected and evaporated in vacuo
at 35C. The residue is crystallized and the product is purified as
described in Example 5. 1.72 g. (68 %, calculated for taurine) of gamma-L-
glutamyl-taurine are obtained.
Example 8
Carbobenzyloxy- gamma-L-glutamyl-taurine, obtained as described
in Example 4, is dissolved in 2 ml. of glacial acetic acid containing 4 moles
of hydrogen bromide. The mixture is allowed to stand at room temperature
- 25 -

1~)5180Z
for 30 minutes, and then evaporated in vacuo at 35C. The residue is tri-
turated several times with ether; the etheral solutions are decanted. The
substance is recrystallized as described in Example 5, to yield gamma-L-
glutamyl-taurine.
Example 9
10 ml. of a 0.01 N aqueous sodium hydroxide solution are added
to the solution of 25.4 mg. ~0.~ mmoles) of gamma-L-glutamyl-taurine in
2 ml. of water, and the mixture is evaporated to dryness in vacuo at 35C.
The white, crystalline residue is dried in a desiccator over phosphorous
pentoxide. The mono-sodium salt of gamma-L-glutamyl-taurine is obtained.
The product is sparingly soluble both in methanol and ethanol. The product
has no sharp melting point; it starts to shrink at about 200C, and
carbonizes at about 250C.
Example 10
10 ml. of absolute methanol, containing 0.5 moles/l. of hydrogen
chloride, are added to 7.5 mg. (30 micromoles) of gamma-L-glutamyl-taurine,
and the suspension is stirred at room temperature for 24 hours. The
product is isolated in pure state by descending paper chromatography. Rf =
0.27 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic acid
and water) and 0.14 (in a 4:1:1 mixture of n-butanol, glacial acetic acid
and water).
Example 11
One proceeds as described in Example 10 with the difference
that ethanol is substituted for methanol. This way the corresponding ethyl
ester, i.e. gamma-~ a-ethyl)-L-glutamyl-taurine is obtained. Rf = 0.37
(in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic acid and
water) and 0.22 (in a 4:1:1 mixture of n-butanol, glacial acetic acid and
water~.
Example 12
25.4 mg. ~0.1 mmoles) of gamma-L-glutamyl-taurine are dissolved
in 100 ~1. of 2 N aqueous sodium hydroxide solution, and a total amount
of 36 ~1. of acetic anhydride and 180 ,ul. of 4 N aqueous sodium hydroxide
- 26 -

1051802
solution are added to the vigorously stirred mixture in three portions.
The mixture is stirred for 5 minutes each after the addition of the
individual portions. Finally the alkaline solution is diluted with water
to 2 ml., and allowed to stand at room temperature for 12 hours. Th.ereafter
the solution is poured onto a 1 cm. x 10 cm. column filled with Dowex
50x2 resin, and the column is eluted with water. 50 ml. of eluate are
collected, and this solution is evaporated in vacuo at 35C. The obtained
N-acetyl-gamma-L-glutamyl-taurine is dissolved in water and purified by
paper electrophoresis using a pH 6.5 buffer. Relative motility (related
to cysteinic acid): 1.22. Rf = 0.25 (in a 15:10:3:12 mixture of n-butanol,
pyridine, glacial acetic acid and water).
Example 13
25.4 mg. (0.1 mmoles) of gamma-L-glutamyl-taurine are treated
with 13 ~1. of benzoyl chloride as described in Example 12. The reaction
mixture is processed as described in Example 12 to obtain N-benzoyl-gamma-
L-glutamyl-taurine, which is purified by paper electrophoresis using a pH
6.5 buffer solution. Relative motility (related to cysteinic acid): 1.06.
Rf = 0.47 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic
acid and water).
Exam~le 14
0.48 g. ~1 millimole) of carbobenzyloxy- ~-L-glutamyl-(gamma-
p-nitrophenylester)-glycine ethyl ester (Acta Chim. Acad. Sci. Hung. 65,
375 /1970/) are dissolved in 6 ml. of ethyl acetate. The solution is
cooled with ice water to 0C, and a solu~ion of 0.08 g. (1 mmole) of
cysteamine in 1 ml. of dimethyl formamide is added. Thereafter 0.14 ml.
~1 mmole) of triethylamine are added dropwise to the solution. A pre-
cipitate starts slowly to separate. The reaction mixture is allowed to
stand in ice water and then at room temperature for one day. The mixture
is diluted with a 1:1 mixture of ethyl acetate and ether, the precipitate
is separated by centrifuging, and washed several times with a 4:1 mixture
of ether and ethyl acetate and finally with ether. The precipitate is dried
over sulfuric acid, then washed successively thrice with 1 N hydrochloric
- 27 -

~051802
acid, twice with water, twice with saturated sodium hydrocarbonate solution
and again twice with water, and dried in vacuo over sulfuric acid. 0.35 g.
(85 %) of carbobenzyloxy- a-L-glutamyl-(gamma-cysteamine)-glycine ethyl
ester are obtained.
Analysis:
Calculated for C18H2506N3S (M = 411-4):
C: 52.6 % H: 6.1 % S: 7.8 %
Found: C: 53.4 % H: 6.5 % S: 7.7 %
IR-spectrum: characteristic maxima at 3310 (MH), 1748 ~ester
carbonyl), 1690 ~C=0 /carbobenzyloxy/) and 1655 ~amide carbonyl) cm 1.
100 mg. of carbobenzyloxy-a -L-glutamyl-~gamma-cysteamine)-
glycine ethyl ester are dissolved in 2 ml. of glacial acetic acid, and 0.5
ml. of 30% hydrogen peroxide are added to the solution. The reaction
mixture is allowed to stand in an ice bath for 4 hours. The progress of the
reaction is monitored by electrophoresis. When the reaction terminates the
mixture is diluted with water and subjected to freeze drying. 0.11 g. of
solid, foam-like carbobenzyloxy- -L-glutamyl-~gamma-taurine)-glycine
ethyl es~er are obtained; yield: 95 %.
Example 15
0.47 g. (1 mmole) of carbobenzyloxy- a-L-glutamyl-~gamma-p-
nitrophenylester)-glycine methyl ester are dissolved in 6 ml. of pyridine.
The solution is cooled in an ice bath and a solution of 0.125 g. ~1 mmole)
of taurine in 2 ml. of water is added, followed by 0.28 ml. ~2 mmoles) of
triethylamine. The reactants should be added in small portions so as to
obtain always a clear solution. The reaction mixture is allowed to stand
at room temperature for three days and then evaporated in vacuo. The oily
residue is triturated with ether and petroleum ether and dried in vacuo
over sulfuric acid. Carbobenzyloxy-a-L-glutamyl-(gamma-taurine)-glycine
methyl ester is obtained.
Example 16
lO0 mg. of carbobenzyloxy- a-L-glutamyl-(gamma-taurine)-glycine
ethyl ester ~prepared as described in Example 14) are dissolved in a mixture
- 28 -

lOS180Z
of 1 ml. of trifluoroacetic acid and 1 ml. of concentrated hydrochloric acid.
The solution is maintained at 35C for three hours in a sealed tube. The
obtained solution is evaporated in vacuo, the residue is triturated several
times with ether and n-hexane, and finally evaporated again. 0.06 g. (88 %)
of a-L-glutamyl-(gamma-taurine)-glycine are obtained as a white, amorphous
substance. On the basis of electrophoresis the product is uniform and
gives a positive ninhydrine reaction.
Analysis:
Calculated for CgH17N3O7S (M = 311.3): S: 10-3 %
Found:S: 10.0 %
IR-spectrum: characteristic bands appear at 3100 (broad, NH3),
3200 ~broad carboxy OH), 1730 (carboxy carbonyl), 1680 (amide carbonyl),
1560 (amide carbonyl), 1220 (intense, sulfonic acid S=O) and 1045 (intense,
sulfonate S=O) cm~l.
20 mg. of the above substance are admixed with 1 ml. of 6 N
hydrochloric acid, and the mixture is heated at 105C for 24 hours in a
sealed tube. After cooling, a sample of the solution is subjected to
electrophoresis. The sample contains glutaminic acid, glycine and taurine.
Example l7
100 mg. of carbobenzyloxy- ~-L-glutamyl-(gamma-taurine)-glycine
methyl ester (prepared as described in Example 15) are treated with 4 ml.
of 2 N hydrobromic acid in glacial acetic acid at room temperature until
complete dissolution takes place (for about 30 minutes). The obtained clear
solution is psured into 30 ml. of ether, and the mixture is allowed to stand
at a cold place for one day. The separated substance is removed by centri-
fuging, washed several times with ether, and dried in vacuo over potassium
hydroxide, sulfuric acid and phosphorous pentoxide. ~-L-glutamyl-(gamma-
taurine)-glycine methyl ester hydrobromide salt is obtained. On the basis
of electrophoresis the obtained product is practically completely pure.
Example 18
The salt obtained according to Example 17 is treated with 2 ml.
of 1 N sodium hydroxide solution for 3 hours under ice cooling. The progress
- 29 -

1051~0Z
of the hydrolysis is monitored by electrophoresis. The reaction mixtur0 is
treated with 10 ml. of Dowex 50 ion exchanger ~H~ form) and freeze-dried.
On the basis of electrophoresisJ the obtained substance still contains im-
purities. The crude product is recrystallized several times from aqueous
ethanol, until the required purity is attained. 40 mg. (59 %) of ~-L-
glutamyl-(gamma-taurine)-glycine are obtained.
IR-spectrum: characteristic bands appear at 3310 (NH), 3100
~broad, NH3), 1730 ~carboxy carbonyl), 1650 (amide carbonyl), 1570 (amide
carbonyl), 1220 ~intense, S=0), and 1045 (intense) cm 1.
Example 19
100 mg. of ~-L-glutamyl-(gamma-taurine)-glycine (prepared as
described in Example 16 or 18) are dissolved in 25 ml. of 0.2 molar
ammonium hydrocarbonate buffer (pH = 8.5), and a solution of 1 mg. of car-
boxypeptidase-A (Serva, Heidelberg) in 0.5 ml. of wa~er is added. The mix-
ture is thermostated at 37~C for 24 hours, and then freeze-dried. The dry
residue contains gamma-L-glutamyl-taurine and glycine. From this mixture
gamma-L-glutamyl-taurine can be separated in pure state by electrophoresis or
by chromatography using Dowex 50 ion exchanger.
Example 20
0 52 g. (4 mval.) of ~-poly-L-glutaminic acid with a polymerization
grade of 80 (Acta Chim. Acad. Sci. Hung. 5, 267 /1955/) are dissolved in 10
ml. of dimethyl formamide, and 1.39 g. (10 mmoles) of p-nitrophenol and 0.82
g. C4 mmoles) of dicyclohexyl carbodiimide are added to the solution under
stirring and ice cooling. After 10 minutes the dicyclohexyl urea starts to
separate. The mixture is stirred at room temperature for one day, and the
separated dicyclohexyl urea is filtered off. 0.3 ml. of glacial acetic acid
are added to the filtrate to convert the non-reacted dicyclohexyl carbodiimide
into dicyclohexyl urea, and the separated substance is filtered off. The
filtrate is poured into a mixture of 100 ml. of ether, 100 ml. of petroleum
ether, 20 ml. of ethyl acetate and 2 ml. of glacial acetic acid. The sep-
arated substance is isolated by centrifuging, washed several times with ether,
and dried in vacuo over sulfuric acid. 0.80 g. of
- 30 -

105180Z
~-poly-L-glutaminic acid-p-nitrophenylester-l are obtained, containing 2.6
mval./g. of p-nitrophenolate.
IR-spectrum: characteristic bands appear at 3300 (NH), 1765
~COONP carbonyl), 1660 (amide carbonyl), 1550 ~amide carbonyl), 1530 (NO2)
and 1360 (NO2) cm 1
0.25 of the a~ove compound are dissolved in 7 ml. of pyridine,
and a solution of 0.125 g. (1 mmole) of taurine in 1 ml. of water and 0.28
ml. (2 mmoles) of triethylamine is added in ten portions to the stirred
mixture. The reactant is added at a rate to obtain always a clear solution.
1 ml. of water is added to the mixture, and the mixture is maintained at
room temperature for 3 days. The solution is evaporated in vacuo, the
residue is dried, and triturated well with ether. The obtained powdery
substance is dissolved in water and the solution is freeze-dried. 0.20 g.
of ~poly-gamma-L-glutamyl-taurine-l are obtained. On the basis of
chromatographical examination the product contains 0.4 % of taurine
contamination.
Analysis: S: 10.1 %
IR-spectrum: characteristic bands appear at 3100-3400 (broad, OH),
1650 ~amide carbonyl), 1550 (amide carbonyl), 1220, 1040 and 600 (sulfonic
acid S=0) cm 1.
Example 21
0.26 g. C2 mval.) ofoC-poly-L-glutaminic acid with a polymerization
grade of 580 (J. Am. Chem. Soc. 80, 4631 /1958/) are swollen and dissolved
in 15 ml. of dimethyl formamide, and 0.69 g. (5 mmoles) of p-nitrophenol
and 0.41 g. (~ mmoles) of dicyclohexyl carbodiimide are added to the stirred
solution. the reaction mixture is stirred for 2 days at room temperature.
0.30 g. of -poly-L-glutaminic acid-p-nitrophenyl ester-2 are obtained.
IR-spectrum: the spectrum is similar to that discussed in
Example 20 but the bands are broader and also an acid carbonyl band appears
at 1720 cm 1.
The above compound is reacted as described in Example 20 to
obtain 270 mg. of freeze-dried d-poly-gamma-L-glutamyl-taurine-2. On the

105~80Z
basis of chromatographical examination the product contains less than
0.4 % of taurine impurity.
Analysis: S: 7.3 %.
IR-spectrum: identical with the above.
Example 22
0.26 g. (2 mval.) of a-L-polyglutaminic acid with a polymerization
grade of 580 are dissolved in 8 ml. of dimethyl formamide, and the solution is
cooled to -10C in a salted ice bath. Upon the addition of 0.28 ml. (2
mmoles) of triethylamine a gel is formed~ which cannot be dissolved even
when adding further 8 ml. of dimethyl formamide and applying vigorous
stirring. 0.28 ml. (2 mmoles) of isobutyl chloroformate are added dropwise
to the mass, and after 30 minutes of activation a solution of 0.16 g.
(2 m~oles) of cysteamine in 2 ml. of dimethyl formamide is added dropwise.
The mixture is stirred at -5C for 2 hours and then at room temperature for
4 hours, finally it is poured into a mixture of 50 ml. of chloroform and
50 ml. of petroleum ether. The separated white precipitate is isolated
by centrifuging, washed several times with petroleum ether containing
chloroform, swollen several times with alcohol, and finally precipitated
with ether. 0.33 g. of a-poly-gamma-L-glutamyl-cysteamine are obtained.
Analysis: S: 14.7 ~.
0.16 g. of ~-poly-gamma-L-glutamyl-cysteamine are suspended
in 5 ml. of glacial acetic acid, and 1 ml. of 30% hydrogen peroxide is
added. The reaction mixture is allowed to stand at room temperature for 3
days. A clear solution is obtained slowly. The solution is diluted with
water, filtered, and the filtrate is freeze-dried. 0.20 g. of white a-poly-
gamma-L-glutamyl-taurine are obtained. On the basis of chromatographical
examination the product contains 0.5 % of taurine impurity.
Analysis: S: 11.9 %
IR-spectrum: identical with those described above.
Example 23
1.083 g. (2.2 mmoles) of carbobenzyloxy-L-glutaminic acid-C a-
benzyl)-gamma-p-nitrophenyl ester are dissolved in 6 ml. of a 2:1 mixture

105~80Z
of pyridine and water, and 278 mg. (2 mmoles) of homotaurine and 0.59 ml.
(4.2 mmoles) of triethylamine are added to the solution. The yellow solution
is allowed to stand at room temperature for 72 hours, and then it is
evaporated in vacuo. The oily residue is dissolved in water, neutralized
with hydrochloric acid, and extracted with ether in an extractor of
continuous operation for 8 hours in order to remove p-nitrophenol. The
aqueous phase is evaporated in vacuo. 1.68 g. of carbobenzyloxy-gamma-
( ~-benzyl)-L-glutamyl-homotaurine are obtained.
Example 24
~he total amount of the product obtained in example 23 is
dissolved in 10 ml. of 50% aqueous ethanol, 0.3 g. of 10% palladium-on-carbon
catalyst are added, and gaseous hydrogen is bubbled through the suspension
for 4 hours. Thereafter the catalyst is filtered off and the filtrate is
evaporated in vacuo. The residue is dissolved in 1-2 ml. of water, passed
through a 1 cm. x 35 cm. column filled with Dowex 50x2 resin ~Hl cycle),
and the column is eluted with water. 50 ml. of eluate are collected, and
this solution is evaporated in vacuo. 440 mg. (82 %) of gamma-L-glutamyl-
homotaurine are obtained as residue. On the basis of paper electrophoresis
performed at pH 6.5 the crude product contains a small amoun~ of neutral
and acidic contaminations ~homotaurine and glutaminic acid). The crude
product can be purified e.g. by preparative electrophoresis.
In paper electrophoresis performed at pH 6.5 and 1.8,
respectively, the substance always migrates towards the cathode. Relative
motility values ~related to cysteinic acid); 0.68 and 0.50, respectively.
Rf = 0.19 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic
acid and water).
Example 25
1.083 g. (2.2 mmoles) of carbobenzyloxy-L-glutaminic acid-(~ -
benzyl)-gamma-p-nitrophenyl ester are reacted with 278 mg. (2 mmoles) of
N-methyl-taurine as described in Example 23. 1.59 g. of carbobenzyloxy-
gamma-(~ -benzyl)-L-glutamyl-N-methyl-taurine are obtained.

1051802
Example 26
1.59 g of the product obtained according to Example 25 are
subjected to catalytic hydrogenation as described in Example 24~ 423 mg.
(79 %) of gamma-L-glutamyl-N-methyl-taurine are obtained.
In paper electrophoresis performed at pH 6.5 and 1.8,
respectively, the substance always migrates towards the cathode. Relative
motility values (related to cysteinic acid): 0.68 and 0.49, respectively.
Rf = 0.16 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic
acid and water).
Example 27
2.87 g. (6.6 mmoles) of carbobenzyloxy-L-glutaminic acid-( a-
benzyl)-gamma-p-nitrophenyl ester are dissolved in 20 ml. of pyridine, and
a solution of 1.25 g. (6 mmoles) of L-cysteinic acid monohydrate in a
mixture of 17 ml. of water and 17 ml. of pyridine is added. 2.6 ml.
(18.6 mmoles) of triethylamine are added to the mixture, and the reaction
mixture is allowed to stand at room temperature for 72 hours. The solution
is evaporated in Yacuo at 30C. The residue is dissolved in 20 ml. of
water, the solution is acidified with concentrated hydrochloric acid, and
washed with 15xlO ml. of ether. The aqueous phase is evaporated in vacuo
at 35C. Carbobenzyloxy-gamma-( a-benzyl)-L-glutamyl-L-cysteinic acid
are obtained.
Example 28
The product obtained according to Example 27 is dissolved in
20 ml. of water, 0.3 g. of 10% palladium-on-carbon catalyst are added, and
hydrogen is bubbled through the suspension for 3 hours. The reaction mixture
is processed as described in Example 24 to obtain gamma-L-glutamyl-L-cysteinic
acid; m.p.: 187C. Relative motility values in paper electrophoresis
(related to cysteinic acid): 1.21 at pH 6.5, and 0.54 at pH 1.8.
Example 29
1.083 g. (2.2 mmoles) of carbobenzyloxy-L-glutaminic acid-( a-
benzyl)-ga~ma-p-nitrophenyl ester are dissolved in 6 ml. of a 2:1 mixture
of pyridine and water, and 282 mg. (2 mmoles) of cholamine phosphate
- 34 -

~05180Z
(US Patent No. 2,730,542) and 0.87 ml. (6.2 mmoles) of triethylamine are
added to the solution. The mixture is allowed to stand at room temperature
for 72 hours and then it is evaporated in vacuo. The residue is precessed
as described in Example 23. 1.25 g. of carbobenzyloxy- gamma-(a -benzyl)-L-
glutamyl-cholamine phosphate are obtained.
Example 30
1 25 g. of the product obtained according to Example 29 are
subjected to catalytic hydrogenation in order to remove the protecting group.
The hydrogenation and the processing of the reaction mixture are identical
with those described in Example 24. 470 mg. (91 %) of gamma-L-glutamyl-
cholamine phosphate are obtained. ~n the basis of paper electrophoresis
this substance contains about 15 to 20% of cholamine phosphate as impurity.
The crude product can be purified e.g. by electrophoresis.
In paper electrophoresis performed at pH 6.5 and 1.8,
respectively, the substance always migrates towards the cathode. Relative
motility values (related to cysteinic acid): 0.75 and 0.36, respectively.
Rf = 0.18 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic
acid and water).
Example 31
526 mg. (1.1 mmoles) of carbobenzyloxy-L-aspartic acid-( a_benzyl)-
~-p-nitrophenyl ester (Chem. Ber. 97, 1789 /1964/) are dissolved in 5 ml.
of pyridine. The solution is cooled to 0C, and a solution of 125 mg.
(1 mmole) of taurine in 2 ml. of water is added in small portions followed
with 0.28 ml. ~2 mmoles) of triethylamine. The reaction mixture is allowed
to stand at room temperature for 48 hours, and then evaporated in vacuo.
The residue is dissolved in 5 ml. of water, and 1 N hydrochloric acid is
added dropwise to the solution until the disappearance of the yellow colour.
The solution is washed with lOx5 ml. of ether in order to remove p-
nitrophenol. The aqueous phase is evaporated in vacuo. 478 mg. of
carbobenxyloxy-~ -benzyl)-L-aspartyl-taurine are obtained.
The total amount of the product obtained according to Example 31

105180Z
is dissolved in 6 ml. of 50% aqueous ethanol, 100 mg. of 10% palladium-on
carbon catalyst are added, and hydrogen is bubbled through the suspension
for 4 hours. The catalyst is filtered off, the filtrate is evaporated
in vacuo, and the triethylamine is removed from the residue as described in
Example 24. 172 mg. (71 %) of ~-L-aspartyl-taurine are obtained. The
product contains a small amount of taurine as impurity, which can be removed
e.g. by electrophoresis.
In paper electrophoresis performed at pH 6.5 and 1.8, respectively,
the substance always migrates towards the cathode. Relative motility values
(related to cysteinic acid): 0.77 and 0.58, respectively. Rf = 0.16 (in
a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic acid and water).
Example 33
526 mg. (1.1 mmoles) of carbobenzyloxy-L-aspartic acid-(~ -
benzyl)- ~-p-nitrophenyl ester are reacted with 139 mg. (1 mmole) of
homotaurine as described in Example 31 to yield carbobenzyloxy~
benzyl)-L-aspartyl-homotaurine.
Example 34
The product of Example 33 is subjected to catalytic hydrogenation
as described in Example 24. 203 mg. of ~-L-aspartyl-homotaurine are obtained;
yield: 84 %
In paper electrophoresis performed at pH 6.5 and 1.8, respective-
ly, the substance always migrates towards the cathode. Relative motility
values (related to cysteinic acid): 0.72 and 0.53, respectively. Rf = 0.17
(in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic acid and
water).
Example 35
Carbobenzyloxy-L-aspartic acid-~ ~benzyl)-~-p-nitrophenyl ester
is reacted with cholamine phosphate as described in Example 29 to obtain
carbobenzyloxy- ~( ~benzyl?-L-aspartyl-cholamine phosphate.
~xa~ple 36
The substance obtained in Example 35 is subjected to catalytic
hydrogenation as described in Example 24 to obtain ~L-aspartyl-cholamine

1051802
phosphate.
In paper electrophoresis performed at pH 6.5 and 1.8,
respectively, the substance always migrates towards the cathode. Relative
motility values ~related to cysteinic acid): 0.81 and 0.40, respectively,
Rf = 0.14 (in a 15:10:3:12 mixture of n-butanol, pyridine, glacial acetic
acid and water).
Example 37
Crude gamma-L-glutamyl-taurine obtained according to Example S, 6,
7, 8 or 19 can be purified by recrys~allization as follows: 300 mg. of the
crude substance are dissolved at room temperature with stirring in S ml. of
dry dimethyl sulfoxide. The opale solution is filtered, and the filter is
washed with 0.5 ml. of dry dimethyl sulfoxide. The filtTate is combined with
the wash, and 55 ml. of absolute ethanol are added. The mixture is allowed
to stand at room temperature for 12 hours. The separated substance is fil-
tered off, washed with 2.5 ml. of absolute ethanol, and dried in a vacuum
desiccator over phosphorous pentoxide until constant weight. 240 mg. of
crystalline gamma-L-glutamyl-taurine are obtained (recovery: 80 %).
In the above procedure ethanol can be replaced by an equal amount
of dry dioxane, ether or acetone. The quality of the crystalline product is
always the same. M.p. (Boetius~: 218-219C. On the basis of layer
chromatography the product is uniform.
Example 38
Carbobenzyloxy-gamma-(~-benzyl)-L-glutamyl-cholamine is prepared
by the method generally applicable for the preparation of glutaminic acid-
amides (Acta Chim. Acad. Sci. Hung. 64, 285 /1970/). 4.14 g. of the obtained
substance are dissolved in 50 ml. of absolute pyridine, and 9 g. of di-
phenylphosphoryl chloride are added. The mixture is maintained at 0C for
12 hours, then diluted with 80 ml. of chloroform. The separated substance
is filtered off, washed with dilute hydrochloric acid and then with water,
finally dried in a desiccator over solid potassium hydroxide. The obtained
substance is dissolved in lS ml. of 3.3 molar hydrogen bromide in glacial
acetic acid. The solution is allowed to stand for 15 minutes and then it

105~80Z
is evaporated in vacuo at 35C. The residue is dried over solid potassium
hydroxide. The dry substance is dissolved in 30 ml. of 1 N sodium hydroxide
solution. The mixture is allowed to stand at room temperature for one hour,
thereafter acidified to pH 4 with acetic acid, and extracted with 3x30 ml. of
ether in order to remove the by-products (phenol and benzyl alcohol). The
aqueous phase is passed through a column filled with Dowex 50 ion exchanger
~H+ cycle), and the column is eluted with water. The eluate is evaporated
in vacuo, and the residue is recrystallized from a 2:1 mixture of acetone
and water. 0.8 g. of gamma-L-glutamyl-cholamine phosphate are obtained.
Example 39
4.68 ml. ~50 mmoles) of phosphorous oxychloride are added dropwise
*o 1.8 ml. of water under cooling and stirring (Biochem. Preparations 6,
76 /1958/), and 1.9 g. ~10 mmoles) of gamma-L-glutamyl-cholamine ~prepared
from carbobenzyloxy-gamma-/a-benzyl/-L-glutamyl-cholamine, see Example 38)
are added iT~ small portions to the stirred mixture. The mixture is stirred
at 60C for 2 hours, then it is allowed to cool, and 0.72 ml. of water are
added dropwise to the stirred mixture. The mixture is allowed to stand at
room temperature for 2 hours, and then 10 ml. of 96 % e~hanol and 10 ml.
of ether are added dropwise. The reaction mixture is allowed to stand at
4C overnight, then 5 ml. of 96% ethanol are added. The separated substance
is filtered off, washed with ethanol and ether, and recrystallized from
aqueous ethanol. 1.75 g. of gamma-L-glutamyl-cholamine phosphate are
obtained.
Example 40
4.14 g. ~10 mmoles) of carbobenzyloxy-gamma-~a-benzyl)-L-
glutamyl-cholamine are dissolved in 40 ml. of pyridine. The solution is
cooled to -10C, and 2.1 g. ~11 mmoles) of p-toluenesulfonyl chloride are
added in small portions to the vigorously stirred mixture. The mixture is
stirred at 0C for 3 hours, and then poured onto 40 g. of ice. The
separated substance is filtered off, washed with water, and recrystallized
from a mixture of ethanol and petroleum ether. The obtained product is
subjected to catalytic hydrogenation as described in Example 5. The dry
- 38 -

lOS180Z
substance obtained after hydrogenation is dissolved in 30 ml. of water,
10.1 g. (40 mmoles) of sodium sulfite heptahydrate are added, the solution is
stirred at 40C for 24 hours, and finally evaporated in vacuo. The residue
is dissolved in a minimum amount of water, the solution is passed through a
column filled with Dowex 50 ion exchanger, and the column is eluted with
water, The eluate is evaporated in vacuo, and the residue is dried over
potassium hydroxide. The crude product is recrystallized from 80% ethanol
to yield 1.6 g. of gamma-L-glutamyl-taurine.
ExamE~41
15 ml. of thionyl bromide are added to 4.14 g. (10 mmoles) of
carbobenzyloxy-gamma-(~-benzyl)-L-glutamyl-cholamine, and the mixture is
stirred for 3 hours. Thereafter the mixture is diluted with ether, the
separated precipitate is filtered off, and recrystallized from a mix~ure of
acetone and petroleum ether. The obtained substance is dissolved in a
mixture of dimethyl formamide and water, and 10 1 g. (40 mmoles) of sodium
sulfite heptahydrate are added in small portions to the stirred mixture. The
mix~ure is stirred at room temperature for 24 hours and then at 50C for 6
hours, and finally filtered. The clear filtrate is evaporated in vacuo,
and the residue is subjected to catalytic hydrogenation as described in
Example 5. The dry substance obtained after hydrogenation is dissolved in
a minimum amount of water, the solution is passed through a column filled
with Dowex 50 ion exchanger, and the column is eluted with ~ater. The
eluate is evaporated in vacuo, and the residue is recrystallized from 80%
ethanol. 1.2 g. of gamma-L-glutamyl-taurine are obtained.
Example 42
3.71 g (10 mmoles) of carbobenzyloxy-L-glutaminic acid- ~benzyl
ester are dissolved in 60 ml. of acetonitrile. The solution is cooled to
-15C, and 1.4 ml. (10 mmoles) of isobutyl chloroformate and 1.4 ml. (10
mmoles) of triethylamine are added dropwise to the stirred mixture. The
mixture is stirred at -15C for 30 minutes, and then 2.05 g. tlO mmoles) of
bromoethylamine hydrobromide, 1.4 ml. ~10 mmoles) of triethylamine and 40
ml. of acetonitrile, cooled to -15C, are added. The mixture is stirred
- 39 -

105180Z
at -15C for 2 hours and then at room temperature for 4 hours. Thereafter
the mixture is filtered, and the filtrate is evaporated in vacuo at 35C.
The residue is dissolved in a mixture of dimethyl formamide and water, and
10 1 g. of sodium sulfite heptahydrate are added to the solution. Thereafter
one proceeds as described in Example 41 to obtain 1.45 g. of gamma-L-glutamyl-
taurine.
Example 43
3.02 g. (10 mmoles) of carbobenzyloxy-L-glutamine sodium salt
(Liebig's Ann. 640, 145 /1961/) are dissolved in S0 ml. of dimethyl formamidc,
12 mmoles of sodium hydride are added in the form of an oily dispersion, and
the mixture is heated for 2 hours under exclusion of air humidity. There-
after a solution of 2.11 g. ~10 mmoles) of sodium bromoethanesulfonate in
50 ml. of dimethyl formamide is added dropwise, and the mixture is heated
for additional 2 hours. The mixture is evaporated in vacuo. The residue
is extracted with ether, then the dry substance is dissolved in water, and
the solution is passed through a column filled with Dowex 50 ion exchanger.
The column is eluted with ~ater. The eluate is evaporated in vacuo, and
the residue is dried over solid potassium hydroxide. The obtained substance
is subjected to catalytic hydrogenation as described in Example 5. The pro-
duct is recrystallized from a mixture of ethanol and water. 1.55 g. ofgamma-L-glutamyl-taurine are obtained.
Example 44
2.58 g. ~10 mmoles) of L-N-~2,6-dioxo-3-piperidyl)-phthalimide
(J. Pharm. Sci. 57, 757 /1968t) are dissolved in absolute ethanol containing
sodium ethylate. The solution is evaporated in vacuo, the residue is
dissolved in 50 ml. of dimethyl formamide, and 2.25 g. (11 mmoles) of sodium
bromoethanesulfonate are added to the stirred solution. The mixture is
heated for 2 hGurs, and then it is evaporated in vacuo. The residue is
dissolved in water. The solution is passed through a column filled with
Dowex 50 ion exchanger, and the column is eluted with water. The eluate is
evaporated in vacuo, the residue is admixed with 100 ml. of 0.5 N
hydrochloric acid, and the mixture is boiled for 3 hours. The solution is
- 40 -

1051802
evaporated, 30 ml. of ethanol and 0.7 ml. of 72% hydrazine hydrate are
added to the residue, and the obtained mixture is boiled for one hour.
Thereafter the mixture is evaporated in vacuo, 25 ml. of 2 N hydrochloric
acid ar~ added to the residue, and the mixture is heated first at 50C for
10 minutes and then allowed to stand at room temperature for 30 minutes.
The separated solid is removed by filtration, the filtrate is evaporated
in vacuo, and the residue is dried in a desiccator over solid potassium
hydroxide. The obtained substance is dissolved in a 90:8:2 mixture of
water, acetic acid and formic acid, and passed through a 2xlO0 cm. column
filled with Dowex 1 ion exchanger. The ion exchanger has been equilibrated
previously with the same solvent mixture. The elution is started with the
solvent mixture of the above composition, and 400 ml. of eluate are
collected. This fraction contains ~-L-glutamyl-taurine. Thereafter the
column is eluted with 0.5 N hydrochloric acid, and 400 ml. of eluate are
collected again. This fraction is evaporated to dryness in vacuo at 35C.
The residue is dried in a desiccator over solid potassium hydroxide and
then recrystallized from 80% ethanol. 1.07 g. of gamma-L-glutamyl-taurine
are obtained.
Example 45
4.43 g. ~10 mmoles) of carbobenzyloxy-L-pyroglutaminic acid
dicyclohexylammonium salt ~Liebig's Ann. 640, 145 /1961/), 1.25 g. (10
mmoles) of taurine and 0.84 g. (10 mmoles) of sodium hydrocarbonate &re
dissolved in 50 ml. of water. The solution is heated for 4 hours (or
allowed to stand at room temperature for 24 hours), and then evaporated
in vacuo. The residue is dissolved in water, the solution is passed
through a column filled with Dowex 50 ion exchanger, and the column is
eluted with water. The eluate is evaporated, and the obtained substance
is subjected to catalytic hydrogenation as described in Example 5. The
crude product is recrystalli~ed from a mixture of ethanol and water. 2.03
g. of gamma-L-glutamyl-taurine are obtained.