Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
4-14572/-
Novel polycyclic hydrazones, processes for their
manufacture, pharmaceutical compositions containing
them, and their use.
The invention relates to novel polycyclic
hydrazones derived from 3-formylrifamycin ~ or SV as
the aldehydo component and a bi- or tri-cyclic N-amino-
piperazine as the hydrazino component, especially a
l-aminopiperazine having a 3,4-anellated mono- or
bi-cyclic ring syste~. The invention relates
especially to hydrazones of the formula
6 R / (CnH2n)~Y
Rif-CH=~- ~ A / ~~(CmH2m) / ~I)
.,
~- !
~2~
-- 2
in which
R , R2, R3, R , R and R6, independently of one
another, each represents a hydrogen atom
or Cl_4-alkyl.
m and n, independently of one another, each
represents an integer from O to 5,
X represents Cl_5-alkylidene, benzylidene
or C1_~-alkoxymethylene,
Y represents Cl_5-alkylidene, Cl_4-
alkoxymethylene, oxy~ thio or optionally
substituted imino of the formula -N~R)-
wherein R represents hydrogen, Cl_4-
alkyl, C3_5-allcenyl, C3_12-cycloalkyl
or phenyl, or and Y together represent 1,2-cycloalkylene or o-
phenylene each of which can be substituted
by from one to three Cl_4-alkyl
radicals, and
Rif represents a radical of rifamycin S
(quinone form) or rifamycin SV (hydro-
quinone form) that is bonded in the
3-position by the free valency and has the
partial formula
CH3C10 lC3 !C3 IC33
OH OH ll
3\f 3 1 1l ~ CH3
~. i ,i~,1~
O C--CO 11
I ~Rif S]
c~3
:~2~
-- 3 --
CH3~0 Ic~3 CH3 !C 3
IH 1H l!
3~/ CH3 OH OH C/ \CH
3 \.~./ ~ /NH
L l I
or l I lo 1H
1 [Rif SV~
CH3
and to salts thereof.
The invention also relates to processes for the
manufacture of compounds of the formula I (including
their salts), to pharmaceutical compositions containing
them and to the manufacture thereof, and to the use of
these compounds and pharmaceutical preparations.
In view of the very close relationship between the
1,4-quinone and 1,4-hydroquinone forms (corresponding
to rifamycin S and SV, respectively~ and the readiness
with which the two forms convert into one another, the
invention relates in all cases to both for~s unless
specifically stated otherwise.
C1 4-alkyl can be ethyl, propyl and butyl, and
also isopropyl, isobutyl, sec.-butyl and tert.-butyl,
but preferably methyl. The alkyl radical in C1_4-
alkoxymethylene has correspondin~ general and preferred
meaningsO C3_5-alkenyl has an analogous structure
with a double bond which is pre~erably located in the
2~ or 3-position; special mention should be made of
allyl and methallyl.
C1 5-alkylidene is, Eor example, pentylidene,
butylidene, 1-~ 2- or 3-methylbutylidene, 1-ethy]-
~2~
-- 4
propylidene, 1,2-dimethylpropylidene, 1- or 2-methyl-
propylidene and, preferably, ~ropylidene, isopropyl-
idene, ethylidene and, especially, methylene~
The divalent radicals -CmH2m- and -CnH2n-,
which connect the piperazine ring A with sy~bols X and
Y, respectively, represent a single valency bond (if
m or n represents 0), C1_5-alkylidene or C2_5-
alkylene. Cl_5-alkyli~ene that separates the
piperazine ring A from X or Y by one carbon atom has
one of the above-mentioned general or preferred
meanings. C2_5-alkylene that separates the piperazine
ring A from X or Y by from 2 to 5 carbon atoms is
derived from a branched or, preferably, straight-chain
alkane in which the two free valencies originate from
two different carbon atoms situated as desired at the
end or in the middle of the chain, and is~ for example,
pentamethylene, 1- or 2-methyltetramethylene, l- or 2-
ethyltrimethylene, 1,1-, 1,2-, 1,3- or 2,2-di~ethyl-
trimethylene, propylethylene, isopropylethylene,
1-ethyl-(1- or 2-)-methylethylene and 1,1,2-trimethyl-
ethylene, and also tetramethylene, 1- or 2-methyltri-
methylene, ethylethylene and 1,1- or 1,2-dimethyl-
ethylene, and preferably trimethylene, propylene and
ethylene. C3_12-cycloalkyl is a monovalent mono- or
bi-cyclic radical of which the individual rings have
from 3 to 8 ring members and can be substituted by from
one to four C1_4-alkyl radicals, for example those
characterised above, but preferably methyl radicals.
There are prefPrred sy~metric combinations of
substituents, that is to say those the presence of
which does not result in the formation of an asymmetry
centre, such as, especially, pairs of the same alkyl
radicals situated at one and the sa~e carbon atom
(geminal), such as occur, for example~ in 4,4-dimethyl-
cyclohexyl or 3,3,4,4-tetramethylcyclopentyl. 1,~-
~2~
-- 5
cycloalkylene is a divalent radical analogous to theabove-characterised cycloalkyl but is preferably mono-
cyclic and has from 5 to 8 ring members, such as, for
example, 1,2-cyclooctylene and 1,2-cyclopentylene, and
especially 1,2-cycloheptylene and more especially 1,2-
cyclohexylene; the two free valencies have the cis or
trans orientation with respect to one another and
form the corresponding linkage with ring B. The cyclo-
alkylene radicals can be substituted in a manner
analogous to the cycloalkyl radicals, such as, for
example, in 4,4-dimethyl-1,2-cyclohexylene or 3,3,S,5-
tetramethyl-1,2-cyclopentylene, but unsubstituted
radicals are preferred. Phenyl or o-phenylene may
also carry from one to Eour of the above-characterised
C1_4-alkyl radicals, especially methyl radicals, but
are preferably unsubstituted.
The ring B anellated with the piperazine ring A
preferably comprises a total of from 5 to 8, especially
5 or 6, and more especially 6, ring members.
Each of the symbols R1 to R6 individually
preferably represents hydrogen; if some of them have a
meaning other than hydrogen then preferably a
maximum of 2 or, more especially, only 1 such
radical(s) is involved, methyl being especially
preferred. An advantageous arrangement is formed by
two identical substituents that are bonded geminally,
that is to say at one and the same carbon atom, and
therefore do not give rise to an additional asymmetry
centre (and, accordingly, to a new pair of
diastereoiso~ers).
Preferred compounds of the formula I are, for
exa~pler those in which ~ represents from 0 to 3 and
n represents from 1 to 4, each of the radicals
CmH2m and CnH2n preferably being straight-chain
and/or separating the piperaæine ring ~ from the
:~2~
-- 5 --
symbols X and Y, respectively, by a maximum of 31
preferably a maximum of 2, carbon atoms, a maximum o
one of the symbols R1 to R6 is other than hydrogen,
in which case it represents C1_4-alkyl, such as
methyl or ethyl, and one of the symbols X and Y
represents ethylidene or methylene whilst the other
represents C1_~-alkylidene, C~ alkoxy~ethylene,
oxy (-O-), thio (-S-~, imino (-NH-), or imino
substituted by Cl_4-alkyl, or X and Y together
represent 1,2-cycloalkylene having from 6 to 8 ring
atoms or o-phenyleneO
Of these, there are more especially preferred, for
example, compounds of the formula I in which m
represents O and n in a preferably straight-chain
radical CnH2n represents from 1 to 4, a maximum of
one of the symbols R1 to R6 is other than hydrogen,
in which case it preferably represents methyl, and one
of the symbols X and Y represents ~ethylene whilst the
other represents ethylidene, propylidene, C1_4-
alkoxy~ethylene or, preferably, methylene, or X and Y
together represent 1,2-cyclohexylene, 1,?-cyclo-
heptylene, 1,2-cyclooctylene or o-phenylene. Of
these, special mention should be made of those in which
m represents 0, CnH2n represents methylene,
trimethylene or, especially, ethylene, Rl represents
methyl or, especially, hydrogen, R2 to R6 each
represents hydrogenr X represents ethylidene or,
especially, methylene, and Y represents propylidene,
isopropylidene, methoxy- or ethoxy-methylene or,
especially, methylene, or X and ~ together represent
1,2-cy_lohexylene or o-phenylene.
~ ccordingly, there are especially preEerred as the
hydrazine component N-aminopiperazines having the
following basic structure which can be substituted by
Cl_4-alkyl and/or C1_4-alkoxy radicals: 3-aminoper-
~z~
- 7 -
hydropyrrolo~1,2-alpyrazine, 3-aminoperhydro-lH-pyrido-
[1,2-a]pyeazine/ 3-aminoperhydropyrazino[1,2-a]azepine
or 3-aminoperhydro-1~-pyrazino[1,2-a]azocine, or 3-
aminoperhydropyrazino[1,2-a]indole, 3-amino-1,2,3,4,-
4a,5-hexahydropyrazino[1,2-a]indole, 3-aminoperhydro-
1~-pyrazino[1,2-a~quinoline, 3-amino~2,3,4,4a,5,6-
hexahy~ro-1~-pyrazino[1,2-a]quinoline.
There are more especially preferred also, for
example, those compounds of the formula I in which m
and n, independently of one other, each represents
from 1 to 3, the radicals CmH2m and CnH2n each
separating the piperazine ring A ~rom the symbols X and
Y, respectively, by a maximum of 2, pref~rably by 1,
carbon atom(s), a maximum o~ one of the symbols R1 to
R6 is other than hydrogen, in which case it
preferably represents methyl, and one of the symbols X
and Y represents ethylidene or methylene whilst the
other represents oxy, thio or imino, it being possible
for the imino to be substituted, preferably in the
manner indicated above, especially by C1_~-alkyl,
more especially by isobutyl or methyl. Of these,
special mention should be made of those in which m
and n each represent 1, R1 represents methyl or,
preerably, hydrogen, R2 to R6 each represent
hydrogen, X represents methylene and Y represents oxy,
thio, imino or C1_4-alkylimino, such as, especially,
i~obutylimino or methylimino. Accordingly there are
especially preferred as the hydrazine component
especially also N-aminopiperazines having the following
basic structure which can be C~ and/or M-substituted by
C1_~-alkyl radicals:
6-aminoperhydropyrazolo[2,1-c]~-oxazine,
6-aminoperhydropyrazolo~2,1-c]p-thiazine, and
3-amino-6-R-perhydro-1~-pyra2ino~1,2-a]pyrazine,
in the last name indicating the substituent of the
- 8 -
imino group ( including hydrogen) .
Very especially preferred are all the compounds o
the formula I mentioned in the Examples in both forms,
that is to say both of the quinone (S) and of the
hydroquinone (SV) series, even where only one form is
expressly mentîoned, and corresponding salts.
Most of the compounds of the formula I may,
according to their individual character, also be in the
form of salts Those compounds having sufficient
acidity, such as, especially, the hydroquinones of the
SV series, can form salts with bases, such as, espe-
cially, inorganic bases, preferably physiologically
tolerable alkali metal salts, especially sodium and
potassium salts. Those compounds of the formula I
having sufficient basicity can be in the form of acid
addition salts, especially physiologically tolerable
salts, with customary pharmaceutically acceptable
acids; of the inor~anic acids special mention should be
made of hydrohalic acids, such as hydrochloric acid,
and sulphuric acid and phosphoric or pyrophosphoric
acid, and of the organic acids especially the sulphonic
acidsl for example the aromatic sulphonic acids, such
as benzene- or ~-toluene-sulphonic acid, embonic acid
and sulphanilic acid, or lower alkanesulphonic acids,
such as methanesulphonic, ethanesulphonic, hydroxy-
ethanesulphonic and ethylenedisulphonic acid, or
alternatively aliphatic, alicyclic, aromatic or
heterocyclic carboxylic acids, such as formic, acetic,
propionic, succinic, glycolic, lactic, ~alic, tartaric,
citric, fumaric, maleic, hydroxymaleic, oxalic, pyruvic,
phenylacetic, benzoic, ~-aminobenzoic, anthranilic,
p-hydroxybenzoic, salicylic and ~-aminosalicylic
acid, and also amino acids, especially naturally
occurring a-amino acids, such as glycine, leucine,
methionine, tryptophan, lysine or arginine, and
:~z~
- 9 -
ascorbic acid. Compounds of the Eormula I that contain
both basic and acidic functional groups may also be in
the form of internal salts.
Some hydrazones derived fro-m 3-formylrifamycin SV
have already been described. In particular, in U.SO
Patent No. 3 342 810 there are described and claimed,
among other antimicrobially active derivatives of the
latter-mentioned primary substance, also hydrazones of
the partial formula ~N-N(R2)R3 in which R2 and
R3, in addition to a number of meanings for each
symbol individually, both together and together with
the nitrogen atom represent a heterocyclic ring having
from 5 to 7 atoms. Apart from this definition in
patent claim 6, the description provides no more
detailed characterisation of the heterocyclic ring;
there are simply listed nine Examples of specific
individual compounds (including data relating to their
biological action) in the Table, column 3, compounds 3
to 14. Of these, special mention is made later in the
text (column 5, lines 64-75, and column 6, lines 30 to
45) oE the hydrazone of 3-formylrifamycin SV with 1-
amino-4-methylpiperazine because o~ its excellent
antituberculotic activity, and this compound is
protected in the specific claim 15~ This compound,
under the generic name rifampicin, has until now been
one of the leading therapeu~ic agents for combating
tuberculosis. Hydrazones having more than one
heterocyclic ring have not been considered or
indicated.
Although riEampicin can be numbered among the best
agents for the treatment of tuberculosis infections, in
some cases its relatively short dwell time in the
organism is a considerable disadvantageO The
preparation of ~edic~ments having an action against
tuberculosis infections analogous to that of rifampicin
~z~
-- 10 --
but having a prolonged duration of action is therefore
one of the most urgent t sks in this field. Until now
it has not been possible to find, even among riEamycin
derivatives modified in other ways, some of which
exhibit a very good antituberculotic action (in
exceptional cases up to three times that of
rifampicin), active ingredients that are of equal value
or even superior to rifampicin with regard to their
long-term action.
It has now been found that the novel compounds
according to the present invention are distinguished
both by a good antituberculotic activity that is
superior to that of rifampicin, especially in vivo,
and by a considerably increased dwell time in the
organism, as can be demonstrated with reference to the
following data.
e~end to Table 1
~1) Hydrazones of 3-formylrifamycin SV; the structure
is characterised by the ring system tB) anellated
to the piperazine ring (A); (1~) - piperazine ring
(A) carries methyl in the 2-position.
(2) Test organism: Mycobacterium tuberculosis TB H3RV
t3) Minimum inhibitory concentration in a plate
test in vitro.
(4~ In vivo test (mice~; administration p.o.
(5) Half-life period of excretion (in hours).
(6) Highest concentration of the active ingredient in
the blood plasma.
(7) Comparison substance: the hydrazone of 3-formyl-
rifamycin SV with 1-amino-4-methylpiperazine.
~21~
- 11 -
Table I:
__
_ . . ~
Antituberculotic Pharmacokinetics
E Active action (2) Mice Rat6
x. ingredient . ___ . .. _ ~ ~ ~ _
~0 2 (13 (3) ~4) (5) (6) (5) (6)
MIC ED50 t/~ Cmax tf2 Cmax
~g/ml mg/kg h ~g/ml h ~g/ml
~_ . ~ ~ __ ~
1 Piperidine 0~03 0~8 20 27~3 17.0 24.5
2 Pyrrolidine 0.1 205 9.1 57.7 13.2 1~.6
3 6-Methyl-
piperidine 0.4 1 14 2206
4 5-Ethyl~
piperidine
Isvmer A 0.01 0~8 55.1 29.5
B- 0003 1 44~6 26~4
S Piperidine; :-
(1A)
Isomer A 002 3 69.3 15 5805 19~7
B 0.4 2 6~ 38~8 44.7 16~4
C O.V6 3 15 23.7
D 0006 3 2S.1 3306
6 Perhydro-
quinoline
Isomer A 0.03 33.4 56.3
B 0.007 40.9 34
7 1,2,3,4-
Tetrahydro-
quinoline O.06 4.~ 32.2 24
8 Thio-
morpholine 0.2 8 8~9 72
9 ~'-~ethy~-
piperazine O D 1
_~_ _~ .__ __.__ ___
Rifampicin(7) 0,03 5.9 6 24 o 8 3 ~ 8 13 ~ 9
_ ~ ______ __ __ ~__
- 12 -
The novel compounds of the formula I can be
manufactured in a manner known per se by means of
well-known general processes, for example, as follows:
a) a 3-formylrifamycin of the formula
Rif-CH=O (II)
in which Rif has the meaning given above, or a
functional derivative thereof, is reacted with an
N-aminopiperazine of the formula
R~l /( CnH2n )~Y~{
~III)
/ - - ~ 4
in which R1 to R6, n, m, X and Y have the
meanings given above, or
b) for the direct manufacture of derivatives of the
S series, the 3-(rifamycin S)-sulphonic acid of the
formula
[Rif S]-S03H (IV)
in which Rif has the meaning given above, is reacted
with the formaldehyde hydrazone of an N-aminopiperazine
of the formula
- 13 -
R\! ,~ CnH2n ~ -Y
CH2--N-N \ N-(CmH2m ~ (V)
in which R1 to R6, n, m, X and Y have the
meanings given above, and, if desired, when a compound
of the formula I in the quinone form is desired, a
compound of the formula I present in the hyaroquinone
form is treated with an oxidising agent, and/or, when a
compound of the formula I in the hydroquinone form is
desired, a compound of the formula I present in the
quinone form is treated with a reducing agent, and/or a
compound of the formula I present in free form is
converted into a salt thereof, or the compound of the
formula I is freed from a salt thereof.
The reaction of a 3-formylrifamycin of the formula
II, or of a reactive functional derivative thereof,
with the hydrazine of the formula III is e~fected in a
manner known per se, for example in accordance with
the above-mentioned ~.S. Patent. ~specially, the ~ree
3-formylriEamycin SV and the N-aminopiperazine (III)
are reacted in approximately equimolar quantities (or
with a slight excess of the latter) and preferably in
the presence of an organic solvent, such as an alcohol,
for example methanol, ethanol or iscpropyl alcohol, an
open-chain ox cyclic ether, for example diethyl ether,
1,2-dimethoxy- or 1,2-diethoxy-ethane, tetrahydrofuran
or dioxan, an aliphatic ester or amide, for example
ethyl acetate or dimethylformamide, and also dimethyl
sulphoxide and acetonitrile. or in a mixture thereof,
at temperatures of from approximately -20 to
~2~
- 14 -
approximately 50C, preferably between zero and room
temperature. The N-aminopiperazine component (III) can
also be in the form of an acid addition salt and the
base can be freed in situ by the addition of a basic
auxiliary, such as an organic alkali metal salt, for
example sodium or potassium acetate, or a tertiary
organic base, such as a tertiary amine, for example
triethylamine, N-methyl- or N-ethyl-piperidine or N-
methylmorpholine, or alternatively a heterocyclic
aromatic base of the type pyridine and its
homologues or quinoline. It is also possi~le for the
aldehyde component of the formula II to be in the form
of a functional derivative~ for example in the ~orm of
an alkali metal salt of the hydroquinone form o~ the
starting material (II), or especially in the form of a
reactive derivative with a functionally modified
aldehyde group, for example in the form of a compound
of the formula
Rif-CH=Z (II~),
in which Rif has the meaning given above and is
especially [Rif S] and Z represents an oximino,
N-substituted imino, unsubstituted or N-(mono- or di-)
substituted hydrazono, or semicarbazono group. The
substituents oE the imino and hydra~ono group are
monovalent hydrocarbon radicals each having a maximum
of 8 carbon atoms, such as, especially, alkyl or
cycloalkyl radicals having a maximum of 7 carbon atoms,
phenyl or benzyl, or analogous divalent radicals that
together with the nitrogen atom form a satueated
monocyclic heterocycle having from 5 to 7 ring members
and optionally contain in the ring an additional hetero
atom, such as oxygen, sulphur(II), nitrogen, or
nitrogen mono-substituted by C1_4-alkyl. There are
~Z~
- 15 -
peeferred those substituents and their combinations
which result in readily volatile amines or hydrazines,
especially those having a boiling point at normal or
reduced temperature of a maximum of 60C, methyl being
especially preferred. When using such a derivative of
the aldehyde component (II), the operation is carried
out, also in a manner known per se, analogously to
the method described above for free aldehyde. I~ the
component (II) is then used in the form of a salt of a
base, it is advantageous to adjust the reaction mixture
to a neutral reaction, for example by using the other
component (the N-aminopiperazine III) in the form of an
acid addition salt, or alternatively by the careful
addition of an acid, such as a carboxylic acid, ~or
example acetic acid. If the aldehyde component (II) is
used in the form of a derivative with a functionally
modified aldehyde group, the operation can advantage-
ously be carried out in a relatively large excess o
the basic component (III) which then acts simultane-
ously as solvent. The reaction conditions, especially
the temperature and pressure, are so adjusted that the
volatile reaction products (for example the amine or
hydrazine of the formula ZH2), which are freed Erom
the starting material (Il) by the exchange reaction,
are removed continuously from the reaction mixture by
distillation. Advantageously the pressure is reduced
in such a manner that the temperature during distilla-
tion does not exceed approximately 60C and preferably
does not exceed approximately 40C. Under similar
conditions it is also possible, however, to carry out
the exchange in an inert organic solvent, such as one
of those mentioned above, for example dimethyl
sulphoxide.
Process variant b) is also carried out in a manner
known ~ se. Reactant V is preferably reacted with
- 16 -
the 3-[rifamycin S]-sulphonic acid (IV) in a molar
ratio of from 1:1 to 5:1, especially of approximately
from 1 1 to 2:1, and advantageously in an inert organic
solvent, such as one of those mentioned above,
preferably a dipolar solvent, for example acetonitrile,
dimethylformamide, hexamethylphosphoric acid triamide
or, especially, dimethyl sulphoxide, the temperature
being from approximately 0 to approximately 70C,
preferably from room temperature to approximately
50C. The reaction is especially carried out in the
presence of an oxidising agent that is suitable for
ox ia ising hydroquinones to quinones, such as,
especially, manganese dioxide, the oxidising agent and
the hydrazone component ~V) being used in an approxi-
mately equimolar ratio.
The rifamycin derivatives of the formulae II and
IV used as starting materials are known. Compounds of
the formulae III and V are also either known or can be
obtained by customary standard processes of synthetic
organic chemistry. Thus, the bi- or tri-cyclic
N-aminopiperazines of the formula III can be obtained,
for example, by nitrosation ~for example by means of
nitrous acid freed in situ or nitrogen dioxide
N204) oE the corresponding N-unsubstituted bi- or
tri-cyclic piperazine of the formula VI defined below
and subsequent conventional reduction of the resulting
nitrosamine, for example by means of a complex hydride,
such as, especially, lithiu~ aluminium hydride, or by
catalytic hydrogenation.
Bi- and tri-cyclic piperazines of the formula
~2~ 6~
W~ / ~ n 2n ~ Y\
C - CH X
NN / ( mM2m) (VI),
C--C
in which R1 to R4, m, n, X and Y have the
general or preferred meanings given above and W
represents R5 and R6 having the definition given
above, can in turn be obtained, for example, by a
simple commonly used synthesis, by condensing a mono-
or bi-cyclic nitrogen-containing heterocyclyl-2-
carboxylic acid ester of the formula
~ nH2n)~~
Ro-O-CO-CH ~
/ (CmH2m) (VII)
H
in which Ro represents Cl_~-alkyl, especially
methyl or ethyl, and m, n, X and Y have the
meanings given above, with an unsubstituted or
substituted ethyleneimine of the formula
R2 R3
N (VIII
.~
- 18 -
in which R1 to R4 have the meanings given above,
and in the resulting piperazone of the formula VI in
which R1 to R4, m, n, X and Y have the meanings
given above and W represents oxo, converting this oxo
group into the substituents R5 and R6 in
conventional manner. If R5 and R6 each represent
hydrogen, this conversion is effected by reduction,
for example with diborane or a complex hydride, such
as, especially, lithium aluminium hydride. If one or
both of the symbols RS and R6 represent(s) alkyl,
the conversion is effected by treatment with a
corresponding organometallic reagent, such as
alkyllithium or, especially, an alkylmagnesium halide,
for example the chloride orr preferably, bromide, in a
suitable inert organic solvent. As is known, the
conditions can be so controlled that a "geminal base"
having two alkyl substituents, or a mono-alkylated
product is obtained; in the latter case, it is
necessary for the primary intermediate of the formula
VI in which W represents an alkyl together with hydroxy
to be reduced further, for example as indicated above
for the oxo group. The operation is especially carried
out analogously to the reaction conditions given in the
following Examples.
Starting materials of the formula V are obtained
from the N-aminopiperazines of the formula III with
formaldehyde under general conditions that are known
for the formation of formaldehyde hydrazones.
In the primary reaction mixture of the process
according to the invention, the two oxidation stages of
the end product, that is to say the 1,4-quinone form of
the S series and the 1,4-hydroquinone form of the
SV series, can be present in admixture. Advantageously,
however, the whole product is isolated in only one of
the two forms, for example in the hy~roquinone form.
~2~
, 9
This mixture is advantageously made uniEorm, as
described in more detail below, by forming only the
hydroquinone form ~derivative of rifamycin SV) by
reduction or forming only the quinone form (derlvative
of rifamycin S) by oxidation.
The conversion according to the invention, if
desired, of a quinone of the formula I [Rif S]
obtainable according to the process into the corres-
ponding hydroquinone [Rif SV], or of a hydroquinone of
the formula I [Rif SV~ obtainable according to the
process into a quinone [Rif S], or the rendering
uniform of a mixture of the two types of compound is
effected by means of reduction or oxidation. This
conversion can be carried out on a product which has
already been isolated or, often more advantageously,
before the isolation of the desired product. The
reduction can be effected by treatment with a reducing
agent, especially a reducing agent that is suitable for
reducing a quinone to the corresponding hydroquinone,
such as an alkali metal dithionite or hydrosulphite,
for example sodium dithionite or hydrosulphite, ~inc
and acetic acid, or, preferably, with ascorbic acid,
and the oxidation can be effected with an oxidising
agent, especially with an o~idising agent that is
suitable for converting a hydroquinone into the
correspondin~ guinone~ such as atmospheric oxygen,
hydrogen peroxide, alkali metal ferricyanide, for
example potassium ferricyanide, a persulphate salt, for
example ammonium persulphate, or manganese dioxide, the
oxidation preferably being carried out under basic
conditions~ The quinones are mostly violet-red
coloured compounds, whilst the hydroquinones are
usually yellow coloured and have a better
crystallisation ability.
The optional salt-formation, and freeing of the
~2~
- 20 -
primary forms of the compounds of the formula I ~rom
their salts is ef~ected in a conventional manner
generally known ~ se. For example, hydroquinones
are converted into the corresponding alkali metal salts
by treatment with a corresponding compound having an
allcaline reaction, especially a hydroxide, carbonate or
bicarbonate; the salts can be converted into free
hydroquinone compounds by acidi~ication, for example
with inorganic acids, such as, especially, hydrohalic
acids. End products of the formula I that have a basic
reaction can be converted into their acid addition
salts, for example, by treatment with an acid that is
suitable for salt-formation, such as one of those
mentioned above, conversely, such a basic primary form
of a compound of the formula I .is freed by treatment
with agents having a basic reaction, such as inorganic
hydroxidesl carbonate and bicarbonates, or organic
bases and ion exchangers. Internal salts are formed,
for example, by customary acido-basic titration to the
neutral point or to the isoelectric point.
The acid addition salts of the novel compounds,
such as, for example, the picrates, can also be used
for the purification of resulting compounds by
converting the free compounds into salts, separating
the salts and obtaining the free com~ounds again from
the salts. In view of the close relationship between
the compounds in free form and in the form of their
salts, hereinbefore and hereinafter the free compounds
should be understood as meaning optionally also the
corrsponding salts, where appropriate and expedient.
The above-described end products of the formula I,
starting materials (III) and (V) and intermediates are
optionally obtained as race~ates (that is to say
mixtures of two antipodes), racemic mixtures tthat is
to say mixtures of two diastereoisomeric racemates~ and
~L2~
- 21 -
diastereoisomeric mixtures (that is to say mixtures oE
two such diastereoisomers that are not antipodes o~ one
another) an~ can be separated into the individual
antipodes in a manner known per se.
~ racemic mixture is produced especially by
reaction of a chiral reactant in racemic form with a
different chiral reactant that is ~lso in racemic form.
If one of the reactants is used in racemic form and the
other is used in the form o~ a single antipode, as is
predominantly the case in the process according to the
invention, a diastereoisomeric mixture is obtained.
Both types of mixture can be separated by physical
methods, there being isolated in -the former case two
racemates and in the latter case two individual
diastereoisomers not related to one another. Of the
separating methods, special mention should be made of
fractional crystallisation, and also various variants
of adsorption and partition chromatography, and, in the
case of readily volatile mixtures, also fractional dis-
tillation and, especially, gas chromatography.
If in the above-described reactions, as is
especially the case in the manufacture of starting
materials (III) and (V), a racemic starting material is
reacted with an achiral reactant, the reaction product
is again obtained in the form of a racemate which, as
is known, can be separated into the individual
antipodes only by using chiral auxiliaries or aids
according to methods known ~ se. A preferred method
consists in converting a racemic free base with an
optically active acid to form a diastereoisomeric
mixture of two acid addition salts, separating this
mixture by suitable physical methods, and converting
each individual diastereoisomer separately into its
components, that is to say the acid and the individual
antipode of the base, in a manner known per se, for
.
- - \
- Z2 -
example by treatment with a relatively strong acid or
base. As optically active acids there are suitable,
~or example, optically active amino acids, especially
naturally occurring a-amino acids of the L series and
their N-acylated derivatives, the optically active
tartaric acids, especially d-tartaric acid and its
derivatives with esterified hydroxy groups, d- and l-
mandelic acid, d-camphorcarboxylic acid and d- or l-
camphor-10-sulphonic acid.
The invention relates also to those forms of the
process according to which a compound obtainable as
intermediate at any stage of the process is used as
starting material and the remaining steps are carried
out, or a starting material is used in the form of a
derivative, for example a salt, or is formed under the
reaction conditions.
In the processes of the present invention it is
preferable to use those starting materials which result
in the compounds described at the beginning as being
especially valuable.
In view of the above-described pharmacological
properties of the novel cGmpounds~ the present
invention also includes the use of the active
ingredients according to the invention alone~ ~or
example together with adjuncts, or in combination with
other active ingredients, especially antibiotics or
chemotherapeutics, as agents for the treatment of
in~ections, especially those caused by tubercle
bacilli, and by bacteria, especially cocci, such as
those mentioned, and both as medicines and as
disinfectants. When used as medicines, the active
ingredients acording to the invention are preferably
administered in the form of pharmaceutical preparations
together with conventional pharmaceutical c~rriers or
adjuncts. The daily doses to be administered, ~or
- 23 -
example, to warm-blooded animals of approximately 70 kg
body weight are, depending upon species, body weight,
age and individual condition, and depending upon the
mode of administration and, esPecially~ on the
sensitivity of the particular causative organis~, from
approximately 50 to approximately 1000 mg.
The invention also relates to pharmaceutical
preparations that contain the compounds of the present
invention as active ingredients and to processes for
their manufacture.
The pharmaceutical preparations according to the
invention are, for example, for enteral, such as
peroral or rectal, and for parenteral administration to
warm-blooded animals. Suitable dosage unit forms,
especially for peroral administration, for example
dragées, tablets or capsules, preferably conkain from
approximately 50 to approximately 500 mg, especially
from approximately 100 to approximately 300 mg, o~ the
active ingredient together with pharmaceutically
acceptable carriers or adjuncts.
Suitable carriers are, especially, fillers, such
as sugars, for example lactose, saccharose, mannitol or
sorbitol, cellulose preparations and/or calcium
phosphates, ~or example tricalcium phosphate or calcium
hydrogen phosphate, also binders, such as starch pastes
using, for example, corn, wheat, rice or potato starch,
gelatine, tragacanth, methylcellulose and/or, if
desired, disintegrators, such as the above-mentioned
starches, also carboxymethyl starch, cross-linked poly-
~inylpyrrolidone, agar, alginic acid or a salt thereof,
such as sodium alginate. Adjuncts are especially flow-
regulating agents and lubricants, for example silica,
talc, stearic acid or salts thereof, such as magnesium
or calcium stearate, and/or polyethylene glycol.
~ragée cores can be provided with suitable coatings
~2~6~
- 24 -
that may be resistant to gastric juices, there being
used, inter alia, concentrated sugar solutions that
may contain gum arabic, talc, polyvinylpyrrolidone,
polyethylene glycol and/or titanium dioxide, or lacquer
solutions in suitable organic solvents or solvent
mixtures, or, for the manufacture of coatings resistant
to gastric juices, solutions of suitable cellulose
preparations, such as acetylcellulose phthalate or
hydroxypropylmethylcellulose phthalate. Colourings or
pigments may be added to the tablets or dragée
coatings, for example for identification purposes or to
indicate different doses o~ active ingredient.
Further orally administrable pharmaceutical
preparations are dry-filled capsules consisting o~
gelatine, ~nd also soft, sealed capsules consisting of
gelatine and a plasticiser, such as glycerine or
sorbitol. The dry-~illed capsules may contain th~
active ingredient in the form of a granulate, for
example in admixture with fillers, such as lactose,
binders7 such as starches, and/or glidants, such as
talc or magnesium stearate, and optionally stabilisers.
In soft capsules r the active ingredient is preferably
dissolved or suspended in suitable liquids, such as
Eatty oils, paraEfin oil or liquid polyethylene
glycols, to which stabilisers may also be added.
There c3me into consideration as rectally
administrable pharmaceutical preparations, ~or
example, suppositories that consist of a combination of
the active ingredient and a suppository base. Suitable
as suppository bases are, ~or example, natural or
synthetic triglycerides, paraffin hydrocarbons,
polyethylene glycols or higher alkanols. It is also
possible to use gelatine rectal capsules that contain a
combination of the active ingredient and a base
material; suitable base materials are, for example,
~ 2~
- 25 -
liquid triglycerides, polyethylene glycols or parafEin
hydrocarbons.
Suitable for parenteral administration are
especially aqueous solutions of an active ingredient in
water-soluble form, for example a water-soluble salt,
also suspensions of the active ingredient, such as
corresponding oily injection suspensions, there being
used suitable lipophilic solvents or vehicles, such as
fatty oils, for example sesame oil, or synthetic fatty
acid esters, for example ethyl oleate, or tri-
glycerides, or aqueous injection suspensions that
contain viscosity-increasing substances, .~or example
sodium carboxymethylcellulose, sorbitol and/or dextran
and optionally also stabilisers~ The active ingred-
ient, optionally toget~er with adjuncts, may also be in
the form of a lyophilisate and can be made into a
solution before parenteral administration by the
addition of suitable solvents.
The pharmaceutical preparations of the present
invention can be manufactured in a manner known
se, for example by means of conventional mixing,
granulating, confectioning, dissolving or lyophilising
processes. Thus, pharmaceutical preparations for oral
use can be obtained by combining the active insredient
with solid carriers, optionally granulating a resulting
mixture, and processing the mixture or granulate, if
desired or necessary aEter the addition of suitable
adjuncts, to form tablets or dragee cores.
The following Examples illustrate the invention
described above but do not limit the scope thereof in
any way. Temperatures are given in degrees Centigrade.
Melting points are not corrected. In thin-layer
chromatography, .silica gel is used as adsorbent and the
solvent mixture is given in ratios by volume.
- 26 -
Example l: The hydrazone of 3-formylrifamycin SV
with 3-aminoperhydro-lH-pyrido[1~2-a~-
pyrazine
A solution of 1.6 g of 3-aminoperhydro-1H-pyrido-
[1,2-a]pyrazine in 10 ml of tetrahydrofuran is added to
a solution of 5 g of 3-formylriEamycin SV in 100 ml of
tetrahydrouran and the whole is stirred at room
temperature for 6 minutes until according to thin-layer
chromatography all the 3-formylrifamycin SV has been
consumed. For working up, the reaction solution is
concentrated ~n vacuo and the residue is taken up in
methylene chloride. The organic phase is washed twice
with dilute aqueous citric acid solution, dried and
concentrated by evaporation. Crude hydrazone is
obtained which, after crystallisation from ethyl
acetate, yields orange-red crystals of the title
compound which melt, with decomposition, at an
undefined temperature. Thin-layer chromatography with
methylene chlorlde/methanol (9:1): Rf = 0.6; mass
spectrum (CDl/CH4, negative): M = 862 (molecular
weight calculated for C47H62N4O1~ = 862)..
A. The sodium salt of the title compound is obtained
.. . . _ . _
by dissolving 3 g of the above free hydrazone in 10 ml
of dioxan, adding a solution of 0.929 9 of sodium
bicarbonate in 10 ml of water and lyophilising the
resulting solution.
B. Oxidation to form the quinone:
A solution of ~ g of the hydrazone 3f 3-formyl-
rifamycin SV with 3-aminoperhydro~lH-pyrido[l,~-a]-
pyrazine (prepared as described above) in 50 ml of
methylene chloride is stirred intensively with
pulverulent manganese dioxide for ~ minutes at room
~2~
- 27 -
temperature; the solid portions are filtered of and
the iltrate is concentrated to dryness by evaporation.
2 g of the hydrazone of 3-formylrifamycin S with
3-aminoperhydro-lH-pyrido[1,2-a]pyrazine are obtained
in the form of an amorphous blue-black solid having no
definite melting point. Molecular weight according to
mass spectrum (MH+ = 861) corresponds to the
theoretiCal value for C46H60N412-
The 3-aminoperhydro-1H-pyrido[1,2-a]pyrazine used
as starting material can be manufactured as follows:
a) Nitrosation:
At 5~C, an aqueous solution of 5.8~ g of
perhydro-1H-pyrido[1,2-a~pyrazine, see M.E. Freed and
A.R. ~ay: J. Org. Chem. 25, 2108 (1960), is adjusted
to pH 1.1 with concentrated hydrochloric acid and,
while cooling to 0-5C, is treated dropwise with a
solution of 3.18 g of sodium nitrite in 5 ml of water,
stirred for a further two hours at 5-10C and
adjusted to pH 13 with approximately 58 ml of an
aqueous 2N sodium hydroxide solution. The reaction
mixture is extracted with three 80 ml portions of
ethyl acetate and the combined organic solutions are
dried with sodium sulphate and concentrated by
evaporation. The oily residue (6.76 g) is used for the
next stage without purification.
b) Reduction:
. ~.
A solution of 6.76 g of crude 3-nitrosoperhydro-1H-
pyrido[1,2-a]pyrazine (prepared according to stage a~
in 30 ml of tetrahydrofuran is added dropwise at reflux
temperature to a stirred suspension of 1.71 g of
lithium aluminium hydride in 150 ml of tetrahydro-
furan. The reaction mixture is stirred at room
temperature Eor a further 3 hours while cooling with
~z~
- 28 -
ice 10 ml of aqueous 2N sodium hydroxide solution and
then 10 ml of water are added and the whole is stirred
at room temperature for a further 2 hours. The
precipitate is filtered off with suction and then
washed on the suction-filter with hot isopropyl
alcohol. The filtrate (including the isopropyl alcohol
portions) is concentrated by evaporation in vacuo and
yields the desired 3-aminoperhydro-lH-pyrido~1,2-a]
pyrazine (6.68 g) in the form of a slightly yellow-
coloured oil of a purity that is sufficient for the
hydrazone formation Aescribed above.
xample 2: The hydrazone of 3-formylrifamycin SV
with 3-aminoperhydropyrrolo[1,2-a]-
pyrazine
A solution of 1.94 g of 3-aminoperhydropyrrolo-
[1,2-a]pyrazine in 10 ml of tetrahydrofuran is added to
a solution of 2 g of 3-formylrifamycin SV in 200 ml of
tetrahydrofuran and the whole is stirred at room
temperature for 10 minutes until according to thin-
layer chromatography all the 3-formylrifamycin SV has
been consumed~ ~or working up, the reaction solution
is concentrated in vacuo and the residue is taken up
in methylene chloride. T~e organic phase is washed
twice with dilute aqueous citric acid solution, dried
and concentrated by evaporation. The crude hydrazone
is obtained which, after crystallisation from ether,
yields orange-red crystals of the title com~ound,
melting point ~ 210C with slow decomposition; thin-
layer chromatography with methylene chloride/methanol
(9~ Rf = 0.55; mass spectrum (DCl/CH4,
negative): M-' = 848 (molecular weight calculated for
C45H60N4O12 = 848).
For the manufacture of the 3-aminoperhydropyrrolo-
~Z9 4~
- 29 -
[1,2-a]pyraæine used as starting material it is
possible, for example, to subject perhydropyrrolo-
[1,2-a~pyrazine, see Mo~ Freed and A.R. Day: J. Org.
Chem. 25, 2108 (1960) and R.L~ Peck and A.~. Day: J.
Heterocyclic Chem. 6, 181, (1963), to nitrosation and
reduction in succession in accordance with Example 1,
preparation a) and b).
xample 3: The hydrazone of 3-formylrifamycin SV
with 3-amino-8-methylperhydro-lH-pyrido-
[1,2-a]pyrazine
A solution of 1.86 g of 3-amino-8-methylperhydro-
lH-pyrido~1,2-a}pyrazine in 10 ml of tetrahydrofuran is
added to a solution of 2 g of 3-formylriEamycin SV in
100 ml of tètrahydrofuran and the whole is stirred at
room temperature for 10 minutes until according to
thin-layer chromatography all the 3-formylrifamycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. The crude
hydrazone is obtained which is separated into two
individual stereoisomers by chromatography over silica
gel; these stereoisomers are further purified by
crystallisation from acetone/ether/hexane.
The two isomers have analogous mass spectra: (FAB,
positive): MH+ = 877 tmolecular weight calculated for
C~7H~4N~O12 = 867).
somer A: m.p. 183-192C (decomposition); thin-layer
chromatography with methylene chloride/-
methanol (9:1): Rf = 0.58;
- 30 -
somer B: m.p. 166-190C ~slow decomposition); thin-
layer chromatography with methylene
chloride/methanol (9:1): Rf = 0.55.
For the manufacture of the 3-amino-8-methyl-
perhydro-1H-pyrido[1,2-a]pyrazine used as starting
material it is possible, ~or example, to subject
8-methylperhydro-lH-pyrido[1,2-a]pyrazine to nitro-
sation and reduction in succession in accordance
with Example 1, preparation a) and ~). The latter
compound can be obtained from 2-methyl-6-piperidine-
carboxylic acid ethyl ester in accordance with the
procedure of Freed and Day, J. Org. Chem. ~5, 2108
~1960).
xample 4: The hydrazone of 3-formylriEamycin SV
with 3-amino-7-ethylperhydro-1H-pyrido-
[~ ]pyrazine
A solution o~ 1.41 g o 3-amino-7-ethylperhydro-
lH-pyrido~1,2-a]pyrazine in 10 ml of ~etrahydrofuran is
added to a solution of 3 g of 3-formylriamycin SV in
100 ml o tetrahydrofuran and the whole is stirred at
room temperature for 20 minutes until according to
thin-layer chromatography all the 3-formylri~amycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation 7 The crude
hydrazone is obtained which is separated into two
amorphous stereoisomers o th~ title compound by
chromatography over 20~ g of silica gel. The two
isomers produce analogous mass spectra (FAB~ negative):
(M - H~ - 889 ~molecular weight calculated for
- 31 _
C48H66N412 8
somer A: m.pO 173-177C (decomposition); thin-layer
chromatography with ethyl acetate/cyclohexane
(2~ Rf = 0 19;
somer B: m.p. 173-180C (decomposition); thin-layer
chromatography with ethyl acetate/cyclohexane
(2:1): Rf = 0.31.
For the manufacture of the 3-amino~7-ethyl-
perhydro-lH-pyrido[1,2-a]pyrazine used as starting
material it is possible, for example, to subject 7-
ethylperhydro-1H-pyrido[1,2-a~pyrazine to nitrosation
and reduction in succession in accordance with Example
1, preparation a) and b). The latter compound can be
obtained from 3-ethyl-6-piperidinecarboxylic acid ethyl
ester in accordance with the procedure of Freed and
Day, J. ~rg. Chem. 25, 2108 t1960~
y~ The hydrazone o~ 3-formylriamycin SV
with 3-amino-2-methylperhydro-1H-pyrido-
[1~2-a~pyrazine
A solution of 5.8 g of 3-amino-2-methylperhydro-1H-
pyrido[1,~-a]pyrazine in 20 ml of tetrahydrofuran is
added to a solution of 20 g of 3-formylrifamycin SV in
500 ml of tetrahydrofuran and the whole is stirred at
room temperature for 10 minutes until according to
thin-layer chromatography all the 3-formylrifamycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. The crude
.
~2~
- 32 -
hydra~one is obtained ~7hich is separated into four
stereoisomers (A, B, C and D) of the title compound by
means of column chromatography over 1.5 kg of silica
gelO All the isomers produce an analogous mass
spectrum (FAB, negative): (M - H) = 875 (molecular
weight calculated for C47~4N4012 = 876)
The isomers are characterised by the following
data: the thin-layer chromatography is carried out with
methylene chloride/methanol (9:1) as the solvent
system.
~.p. Rf
Isomer A 176-182 (decomposition) 0.44
B 172-178 (decomposition) 0041
C 155-190Q (decomposition) 0.35
~ 170-190 (decomposltion) 0.32
The sodium salt of isomer B is ~ormed by
adding an aqueous solution of 0.24 g of sodium
bicarbonate to a solution of 2.5 g of isomer B and
lyophilising the resulting c;olution.
For the manufacture of the 3-amino-2-methyl-
perhydro-lH-pyrido[1,2-a]pyrazine used as starting
material it is possible, for example, to subject
2-methylperhydro-1H-pyridor1,2-a]pyrazine~ see C.
Winterfield and G. Gierenz: Chem. Ber. ~2, 240
~1959), to nitrosation and reduction in succession in
accordance with Example 1, preparation a) and b).
xample 6: The hydrazone o 3-formylrifamycin SV
with 3-aminoperhydro-1H-pyrazino-
[1,2-a]quinoline
solution of 3.48 g of 3-aminoperhydro-1H-
~2~
- 33 -
pyrazino[1,2-a]quinoline in 10 ml of tetrahydrofuran is
added to a solution of 5 g of 3-formylrifamycin SV in
150 ml of tetrahydrofuran and the whole is stirred at
room temperature for 5 minutes until according to
thin-layer chromatography all the 3-formylrifamycin SV
has been consumed. ~or working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. A crude mixture
of four stereoisomeric hydrazones is obtained from
which two stereoisomers (A and B) of the title compound
are isolated in pure form by column chromatography over
200 g of silica gel. The two isomers produce an
analogous mass spectrum (FAB, negative): (M - H)
= 915 (molecular weight calculated for C50H68N4O12
= 916).
Isomer A: m.p. 165-170C (decomposition~; R~ = Q.5
Isomer B: m.p 168-180C ~decomposition?; Rf = 0142.
~ The thin-layer chromatoqraphy is effected with
methylene chloride/methanol (9:1) as the solvent
system.]
For the manufacture of the 3-aminoperhydro-1H-
pyrazino[1,2-a]quinoline used as starting material it
is possible, for example, to subject perhydro-lH-
pyrazino[1,2 a]quinoline to nitrosation and reduction
in succession in accordance with Example 1,
preparation a) and b). The latter compound can be
obtained from 2r3,4,4a,5,6-hexahydro 1H-pyrazino-
[1~2-a]quinoline, see Swiss Patent Speciication No.
498 849 r by catalytic hydrogenation on platinum oxide
in glacial acetic acid.
- 34 -
Example 7: The hydrazone of 3-formylrifamycin SV
with 3-amino-2,3,4,4a,5,6-hexahydro~
pyrazinol1,2-a3quinoline
A solution of 0.57 g of 3-amino-2,3,4,4a,5,6-
hexahydro-lH-pyrazino[1,2-a]quinoline in 10 ml of
tetrahydrofuran is added to a solution of 2.5 g of
3-formylrifamycin SV in 50 ml of tetrahydrofuran and
the whole is stirred at room te~perature for 10 minutes
until according to thin-layer chromatography all the
3-formylrifamycin SV has been consumed. For working
up, the reaction solution is concentrated in vacuo
and the resi~ue is taken up in methylene chloride. The
organic phase is washed twice with dilute aqueous
citric acid solution, dried and concentrated by
evaporation. The crude hydrazone is obtained whichr
after crystallisation from ether/hexane, yields the
crystalline title compound. M.p. 173-180C
(decomposition); thin-layer chromatography with
methylene chloride/methanol (9:1): Rf = 0.60. Mass
spectrum (~CI/CH4, negative): M = 910 (molecular
weight calculated ~or C50H62N4O12 - 910).
For the manufacture of the 3-amino-2,3,4,4a,5,6-
hexahydro-lH-pyrazino~1,2-a]quinoline used as starting
material it is possible, for example, to subject
2,3,4,4a,5,6-hexahydro-lX-pyrazino[1,2-alquinoline, see
Swiss Patent Specification No. 498 849, to nitrosation
and reduction in succession in accordance with
Example 1, preparation a) and b).
.
Example 8: The hydrazone of 3-formylriEamycin SV
with 6-aminoperhydropyrazolo[2,1-cl-
_-thia~ine
A solution of 1.0 g of 6-aminoperhydropyrazolo-
- 35 -
[2,1-c~p-thiazine in 10 ml of tetrahydrofuran is
added to a solution of 3 g of 3-formylrifamycin SV in
50 ml of tetrahydro~uran and the whole is stirred at
room temperature for 10 minutes until according to
thin-layer chromatography all the 3-~ormylrifamycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. The crude
hydrazone is obtained which, after crystallisakion from
acetone/ether/hexane, yields the crystalline title
compound, m.p. 173-181C ~decomposition); Rf = 0~71
[thin-layer chromatography with methylene chloride/-
methanol (9:1)]. Mass spectrum (F~B, negative):
(M - H) = 879 (molecular weight calculated for
C45~60N4O12S = 880).
For the manufacture of the 6-aminoperhydropyrazolo-
[2,1-c]p-thiazine used as starting material it is
possible, or example, to subject perhydropyrazolo-
~2,1-c]~-thiazine to nitrosation and reduction in
succession in accordance with Example 1, preparation a)
and b)o The latter compound can be obtained from thio-
morpholine-2-carboxylic acid ethyl ester in accordance
with the procedure of Freed and Day, J. Org. Chem.
25, 2108 ~1960).
Example 9: The hydrazone of 3-formylrifamycin SV
with 3-amino-6-methylperhydro-lH-pyrazino-
[1l2-a~pyrazine
~ solution of 2.04 g of 3-amino-6-methylperhydro-
lH-pyrazino[1,2-a]pyrazine in 10 ml of tetrahydrofuran
is added to a solution of 3 g of 3~formylrifamycin SV
in 100 ml of tetrahydrofuran and the whole is stirred
~ , ,
~4~
- 36 -
at room temperature for 15 minutes until according to
thin-layer chromatography all the 3-formylrifamycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. The crude
hydrazon~ is obtained which, after crystallisation from
acetone/ether, yields a crystalline mixture of two
stereoisomers of the title compound, which mixture has
a melting point of 170C ~decomposition~ and in thin-
layer chromatography with methylene chloride/methanol
(9:1) produces two products with RfA = 0-47 and
RfB = 0.41. Mass spectrum (FAB, negative):
(M ~ H) = 876 (molecular weight calculated for
C46H63NsO12 877)
For the manufacture of the 3-amino-6-methyl-
perhydro-1H-pyrazino[1,2-a]pyrazine used as starting
material it is possible, for example, to subject 6-
methylperhydro-lH-pyrazino~1,2-a]pyrazine, see H.J.
Beim and A.~. Day: J. Heterocyclic Chem. 14, 307
~1977), to nitrosation and reduction in succession in
accordance with Example 1, preparation a) and b).
xample 10: The hydrazone of 3-formylrifamycin SV
with 3-amino-6-isobutylperhydro-1H-
pyrazino[l,~-a]pyrazine
A solution of 1.73 g of 3-amino-6-isobutyl-
perhydro-lH-pyrazino[1,~-a]pyrazine in 10 ml of
tetrahydrofuran is added to a solution of 3 g of
3-formylrifamycin SV in 100 ml of tetrahydrofuran and
the whole is stirred at room temperature for 60 minutes
until according to thin-layer chromatography all the
3-formylrifamycin SV has been consumed. For working
- 37 -
up, the reactinn solution is concentrated in vacuo
and the residue is taken up in methylene chlori-3eO The
organic phase is washed twice with di].ute aqueous
citric acid solution, dried and concentrated by
evaporation. The crude hydrazone is obtained which,
after column chromatography over 200 g of silica gel,
yields purified title compound, m.p. 153-170C
(decomposition): Rf = 0.42 [thin-layer chromato-
graphy in methylene chloride/methanol (9:1)]~ Mass
spectrum (F~BJ negative): tM - H) = 918 (molecular
weight calculated for C49H69N5O12 = 919).
For the manufacture of the 3-amino~6-isobutyl-
perhydro-1H-pyrazino[1,2-a]pyrazine used as starting
material it is possible, for example, to subject
6-isobutylperhydro-lH-pyrazino[1,2-a]pyra~ine,
prepared in accordance with HoJ~ Beim and A.R. ~ay: J~
Heterocyclic Chem. 14, 307 (1977), to nitrosation and
reduction in succession in accordance with Example 1,
preparation a) and b).
xample 11: The hydrazone of 3-formylriEamycin SV
with 3-amino-6-cyclopentylperhydro- 1H-
pyrazino[1,2-a]pyrazine
A solution of 1.8 g of 3-amino-6-cyclopentyl-
perhydro-tH-pyrazino[1,2-a]pyrazine in 10 ml of
tetrahydrofuran is added to a solution of 3 g of 3-
formylriEamycin SV in 50 ml of tetrahydrofuran and the
whole is stirred at room temperature or 15 minutes
until according to thin-layer chromatography all the
3-formylri~amycin SV has heen consumed. For working
up, the reaction solution is concentrated in vacuo
and the residue is taken up in methylene chloride~ The
organic phase i5 washed twice with dilute aqueous
citric acid solution~ dried and concentrated by
~2~
- 3~ -
evaporation. The crude hydrazone is obtained which,
after chromatography over 200 g of silica gel, yields
the title compound. Mass spectrum (FAB, negative):
(M - H)- = 930 (molecular weight calculated for
C50~69N5Ol2 9
For the manufacture of the 3-amino-6-cyclopentyl-
perhydro~ pyrazino~1,2-a]pyrazine used as starting
material it is possible~ for example, to subject 6-
cyclopentylperhydro-lH-pyrazino[1,2-a]pyrazine,
prepared according to H.J~ Beim and A.~. ~ay: J.
Heterocyclic ChemO 14, 307 (1977), to nitrosation
and reduction in succession in accordance with
Example 1, preparation a) and b).
xample 12: The hydrazone of 3-formylrifamycin SV
with 6-aminoperhydropyrazino[2,1-c]-
~-oxazine
A solution of 1.94 g of 6-aminoperhydropyrazino-
[2,1-c]P-oxazine in 10 ml of tetrahydrofuran is
added to a solution of 3 g of 3-formylri~amycin SV in
100 ml of tetrahydrofuran and the whole is stirred at
room temperature for lO minutes until according to
thin-layer chromatography all the 3-formylrifamycin SV
has been consumed. For working up, the reaction
solution is concentrated in vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and cor.centrated by evaporation. The crude
hydrazone is obtained which, after crystallisation from
ethyl acetate/cyclohexane, yields orange-red crystals
of the title compound. Mass spectrum (FAB, negative):
(M - H)- = 863 ~molecular weight calculated for
C45H60N4Ol3 = 864).
For the manu~acture o the 6-aminoperhydropyrazino;
2~
- 39 -
[2,1-c]p~oxazine used as starting material it is
possible, for example, to subject perhydropyrazino-
[~,1-c]p-oxazine to nitrosation and reduction in
succession in accor~ance with Example 1, preparation a)
and b). The latter compound can be obtained from
morpholino-2-carboxylic acid ethyl ester in accordance
with the procedure of Freed and Day, J. Qrg.. Chem.
25, 210~ (1960).
xample 13: The hydrazone of 3-formylrifamycin SV
with 3-amino-7-methoxyperhydro-lH-
pyrido[1,2-a]pyrazine
A solution of 1.37 g of 3-amino-7-methoxyperhydro-
lH-pyrido[1,.2-a]pyrazine in 10 ml of tetrahydrofuran is
added to a solution of 3 g of 3-formylrifamycin SV in
100 ml of tetrahydrofuran and the whole is stirred at
room temperature for 60 minutes until according to
thin-layer chromatography all the 3-formylri~amycin SV
has been consumed. For working up, the reaction
solution is concentrated _ vacuo and the residue is
taken up in methylene chloride. The organic phase is
washed twice with dilute aqueous citric acid solution,
dried and concentrated by evaporation. The crude
hydrazone is obtained which, after column chromato-
graphy over 200 g of silica gel, yields puri~ied title
compound~ ~ass spectrum (FAB, negative): (M - H)
= 891 (molecular weight calculat~d for C47H64N4O~3
= 892).
For the manufacture of the 3-amino-7-methoxy-
perhydro-1H-pyrido[1,2-a]pyrazine used as starting
material it is possible, ~or example, to subject 7-
methoxyperhydro-lH-pyrido[1,2-a]pyrazine to nitro-
sation and reduction in succession in accordance with
Example 1, preparation a) and b)~ The latter compound
-` ~2~
- 40 -
can be obtained from 2-methoxy-6-piperidinecarboxylic
acid ethyl ester in accordance with the procedure of
Freed and Day, J. Org. Chem. 25~ 2108 (1960)o
Example 14: Capsules, each containing 250 mg of the
hydrazone of 3-formylriEamycin SV with
3-aminoperhydro-1~-pyrido[1,2-a]pyrazine,
can be manufactured as follows:
Composition (for 10Q0 capsules):
hydrazone of 3-formylrifamycin SV
with 3-aminoperhydro-lH-pyrido-
[1,2-a]pyrazine 250.0 g
corn starch 50.0 g
polyvinylpyrrolidone 15.0 g
magnesium stearate 5.0 g
ethanol q.s
The active ingredient and the corn starch are
mixed together and moistened with a solution of the
polyvinylpyrrolidone in 50 g of ethanol. The moist
mass is pressed through a sieve of 3 mm mesh width and
dried at 45C. The dry granulate is passed through a
sieve o~ 1 mm mesh width and mixed with 5 g of
magnesium stearate. 0.320 g portions of the mixture
are introduced into dry-fill capsules, size 0.
Capsules containing a dose, having an equivalent
action, o each individual product from Examples 2 to
13 are manufactured in analogous manner.
