Note: Descriptions are shown in the official language in which they were submitted.
10559Z9
This application is divided out of our application Serial No.
165,831, filed March 12, 1973.
The present invention relates to a new penicillanic acid derivative
which is effective in treatment of infectious diseases caused by bacterial
microorganisms and to methods for its preparation.
Our application Serial NoO 165,831 relates to new esters of
amidlnopenicillanic acids of the formula
R S / CH3
N-CH=N - CH - CH C
R2 / ¦ l ¦ CH3
CO - N CH - CoOR3
and pharmaceutically acceptable salts thereof, wherein Rl and R2, which are
the same or different, are alkyl groups containing from 1 to 10 carbon atoms,
Rl and R2 together with the adjacent nitrogen atom form a heterocyclic ring
system, R is selected from the group consisting of
fH3
-CH-o-co-R4
and
R5
-CH-0-COO-R
in which radicals R4 is selected from the group consisting of alkyl groups
containing from 1 to 8 car~on atoms, and phenyl; R5 is selected from the
group consisting of hydrogen, methyl and ethyl, with the proviso that when
and R together with the adjacent nitrogen atom form a hexahydro-lH-azepine
ring, R3 is -CH-o-Coo-R4 and R5 is methyl, R4 is not ethyl.
This invention relates to the compound l'-ethoxycarbonyloxy-ethyl-6-
(hexahydro-lH-azepin-l-yl) methyleneaminopenicillanate of formula I
~ \ / \ / 3
I N - CH = N - CH CH C
CH3 CH3 0
CO - N - CH - COO - CH - 0 - C - 0 - C2H5
~0559Z9
and its pharmaceutically acceptable salts.
The compound of the invention is of value in the treatment of in-
fectious diseases in man or animal caused by bacterial organisms. It may be
isolated and used as such but also may be used in the form of salts with
pharmaceutically acceptable organic or inorganic acids. Examples of
suitable acids are hydrochloric acid, hydrobromic acid, sulphuric acid,
phosphoric acid, acetic acid, tartaric acid, citric acid, and fumaric acid.
The compound contains asymmetric atoms, giving rise to different
diastereoisomeric forms which also all are biologically active. It is to be
understood that the invention comprises the pure diastereoisomers as well as
mixtures of them.
Penicillanic acid derivatives of the general formula II
CN-CH=N-CH CH/ \C / 3
CH3 II
CO N CH COOH
are known to have strong antibacterial activity especially against
gramnegative organisms (Canadian Patent NO 914,165). They are, however, not
well absorbed by the oral route and have to be given by injection. It is one
purpose of the present invention to provide an ester of a compound of formula
II, which is well absorbed orally and hydrolysed within the body to give
~0559Z9
blood and organ levels of the compound of formula II that are adequate for
the treatment of infectious diseases caused by bacteria sensitive to penicil-
lanic acids of the formula II. To achieve the full antibacterial activity
of the penicillanic acid II it is necessary to choose such ester groups that
are rapidly hydrolyzed in vivo. It is an essential feature of the present
invention to provide an ester group that is rapidly hydrolyzed in the body
after oral absorption.
The compound of the invention with the formula I is well tolerat-
ed, gives a low frequency of side-effects and may readily be used in phar-
maceutical preparations, either as such or in the form of its salts, and can
be intermixed with solid carriers or adjuvants or both. In such preparations
the ratio between the therapeutic substance and the carriers and adjuvants
may vary between 1% and 95%. The preparation may either be processed to for
instance tablets, pills or dragees or can be supplied to medical containers,
such as capsules or as regards mixtures they can be filled in bottles.
Pharmaceutically acceptable, organic or inorganic, solid or liquid carriers
may be used, suitably for oral or enteral administration or for topical
application, in manufacturing the preparations. Gelatine, lactose, starch,
magnesium stearate, talc, vegetable and animal fats and oils, vegetable
rubber and polyalkylene glycol and other known carriers for pharmaceuticals
are all suitable for manufacturing preparations of said compound. Moreover,
the preparation may contain other pharmaceutically active components, being
suitably administrable together with the compounds of the invention when
treating infectious diseases, for instance other suitable antibiotical sub-
stances, e.g. gentamycin and polymyxin.
In the treatment of bacterial infections in man, the compound of
the invention is for example administered in amounts corresponding to 5 to 20
mg/kg/day, preferably in the range of 10 to 100 mg/kg/day in divided dosages,
e.g. two, three or four times a day. It is administered in dosage units
containing e.g. 175, 350, 500 and 1000 mg of the compound.
-- 3 --
lOS59Z9
The compound of the invention or a salt of the compound can be
prepared by reacting a reactive derivative of an amide or thioamide of the
formula III
CN_CH=R III
where R is 0 or 5, with an ester of 6-aminopenicillanic acid of the formula
IV or a salt thereof.
/ \ / 3 IV
7 f CH
C0 - N CH - CO0 - CH3- 0 - 8 o C2H5
The reactive derivatives of the amides or thioamides of formula III
are acid amide halogenides or dialkylsulphate complexes of acid amides or
acid amide acetals. The former two reagents may be obtained according to
known methods by treatment of compounds of the formula III with halogenating
agents like phosgene, oxalyldichloride, thionyl chloride or thionyl bromide
or with a dialkylsulphate like dimethyl sulphate. The reactions with the
halogenating agents are performed in inert dry organic solvents like diethyl-
ether, toluene, benzene, chloroform or carbon tetrachloride~ The halogenides
are usually obtained as hygroscopic precipitates.
Treatment of the acid amide dialkylsulphate complexes with strong
bases, e.g. sodium methoxide, converts them into acid amide acetals of the
formula (V)
~ N-CH(oR7)2 V
where R7 is a lower alkyl group originating from the dialkylsulphate, which
also can be reacted with the esters of 6-aminopenicillanic acid of formula IV
to give the compound of the invention.
The ester of 6-aminopenicillanic acid of formula IV, i.e. l-ethoxy-
carbonyloxy-ethyl 6-aminopenicillanate, may be prepared by treatment of 6-APA
with compounds C2H5-o-~-o-C~H-3Y1, where Y is halogen or a functionally equiva-
10559Z9
lent group capable of reacting with a carboxy group with formation of an esterlinkage, such as an organic sulphonic acid residue. The reaction is prefer-
ably performed in organic solvents like dimethylformamide, dimethylsulphoxide
or hexamethylphosphoramide. The preparation of this compound is described in
our Canadian Patent No. 960,211.
Alternatively 6-acylaminopenicillanic acid with an acyl group that
can be removed wicthout destruction of the penicillin ring system is treated
with C2H5-0-C-0-CH-Yl wherein yl has the meaning specified above, to give an
ester of 6-acylamino penicillanic acid from which the acyl group is then re-
moved to give the ester of 6-aminopenicillanic acid of the formula IV. A
preferred method consists of reacting a salt, e.g. the sodium, potassium or
tetraalkylammonium solt cf 6-phenylacetamido penicillanic acid (benzylpeni-
cillin) with C2H5-0-C-0-dH-Yl in an organic solvent like chloroform, methyl-
enechloride, acetone, dimethylformamide, dimethylsulphoxide or hexamethyl-
phosphoramide or in a mixture of an organic solvent and water~ e.g. aqueous
acetone or dioxane to give the corresponding ester of benzylpenicillin. The
phenylacetyl side chain is then removed according to the method described in
United States patent No. 3,697,515 or South African Pat. publication 67/2927
by treatment with phosphorous pentachloride in presence of a tertiary organic
base to give an imino chloride which is reacted with an alcohol like propanol
to give the corresponding imino ether which is hydrolyzed by addition of water
or alcoholized by addition of alcohol, to give the ester IV. Alternatively
the phenylacetyl side chain may be removed by enzymatic hydrolysis using an
E.coli acylase according to the method described in French Patent 1,576,027.
In still aOnothcHr method N-protected 6-aminopenicillanic acids are
reacted with C2H5-0-C-0-CH-Yl to give the corresponding ester from which the
protecting groups are removed to give the comp~nds of the general formula IV.
Examples of protecting groups which can be used are the benzyloxycarbonyl
group which is removed by catalytic hydrogenation, the o-nitro-phenylsulphenyl
group which can be removed by treatment with nucleophilic agents at acid pH
-- 5 --
1055929
(Japanese Patent 505,176), and the trityl group which can be removed by mild
acid hydrolysis.
Alternative methods can be used for the preparation of the com-
pound of the invention. 6-formamidopenicillanic acid may be converted into
as ester of the formula (VI)
/ S \ ~ H3 VI
HCONHCH - CH C
CO - N H - CooC9H-o-lC-o-c H
by reaction with C2H5-o-~-o-~H-3Yl under the conditions previously indicated.
Treatment of an ester of 6-aminopenicillanic acid, i.e. a compound of formula
IV, with an l,l-dihalogendimethyl ether, e.g. l,l-dichlorodimethyl ether, in
presence of a tertiary organic base, gives a reactive derivate of the com-
pound of formula VI which reactive derivative reacts with an amine of the
formula (VII):
CNH VI I
to give the compound of formula I.
A third method consists of reacting compounds of formula II, suit-
ably in the form of a salt, e.g. a sodium, potassium, calcium, triethyl-
ammonium or tetraalkylammonium salt, with a compound C2H5-0-~-0-~H-Yl wherein
Y has the meaning specified above to give the compound of the invention.
The reaction is suitably performed in organic solvents like chloroform,
methylenechloride, acetone, dimethylformamide, dimethylsulphoxide or hexa-
methylphosphoramide or in aqueous organic solvents like aqueous dioxane.
As described above the starting material may be in the form of a
salt, for instance a sodium, potassium, calcium or trialkylammonium salt, in
some of the ways for the preparation of the compounds of the invention.
In addition, tetraalkylammonium salts and other analogues salts
such as salts where the cation has the formula
AlA2A3A4N (~3
in which formula A is selected from the group consisting of straight and
-- 6 --
iO559Z9
branched alkyl groups containing from 3 to 6 carbon atoms, substituted and
unsubstituted aryl, and substituted and unsubstituted aralkyl, and wherein
A , A3 and A , which are the same or different, are selected from the group
consisting of straight and branched alkyl groups containing from 1 to 6 car-
bon atoms, provided that A , A3 and A are alkyl with 3-6 carbon atoms when
A is alkyl, may be used.
Illustrative examples of suitable combinations of A , A , A3 and
A in the quaternary ammonium ion A A A3A N ~ are given below:
Table I. Examples of suitable combinations of the radicals
A1-A4 in the A1A A3A N ~ ion
. . _
A A2 A3 - A4
n-propyl n-propyl n-propyl n-propyl
i-propyl i-propyl i-propyl i-propyl
n-butyl n-butyl n-butyl n-butyl
i-butyl i-butyl i-butyl i-butyl
n-pentyl n-pentyl n pentyl n-pentyl
n-hexyl n-hexyl n-hexyl n-hexyl
phenyl methyl methyl methyl
phenyl ethyl ethyl ethyl
p-tolyl ethyl ethyl ethyl
p-chlorophenyl ethyl ethyl ethyl
When the radicals A - A all are different the resulting ion con-
tains an asymmetric centre and may occur in two enantiomeric forms. Epimeric
forms can occur if A , A , A3 and/or A contain one or more asymmetric car-
bon atoms.
Examples of quaternary ammonium ions containing an asymmetric cen-
tre are given in Table II below:
Table II - Examples of quaternary ammonium ion A A A3A N
containing an asymmetric centre
10559Z9
Al A2 A3 A4
benzyl n-propyl i-propyl n-butyl
benzyl n-propyl i-propyl sec.butyl
benzyl n-propyl n-butyl sec.butyl
n-propyl n-propyl n-butyl sec.butyl
n-propyl n-propyl n-propyl sec.butyl
n-propyl n-propyl n-propyl sec.pentyl
n-propyl n-propyl n-propyl sec.hexyl
n-propyl n-propyl n.butyl sec.hexyl
The use as described above of a quaternary salt form of the start-
ing material for the preparation of the compounds of this invention is not
previously described in the literature pertaining to this technical field.
In this method the preferred cation is the tetraalkylammonium ion, particu-
larly the tetrabutylammonium ion. The preferred solvents are chloroform,
methylenechloride and acetone.
The quaternary ammonium salt form of the above described starting
materi~l may be prepared by reacting the starting material in question with
a quaternary ammonium salt of the formula
A A A A n ~ B ~
wherein A , A , A3 and A have the meanings specified above and B is a suit-
able anion such as HS04 ~ , CL ~ or CH3C00 ~ to the formation of a quater-
nary salt of the starting material.
The salts of the formula above which contains B as the anion may
be prepared in known manner analogous as described in for instance Belgian
patent 751,791. The anion B ~ is in the preferred embodiment HS04 ~ .
The following examples will further illustrate the invention. Ex-
ample 1 illustrates the preparation of the compound of this invention, i.e.
1'-ethoxycarbonyloxy ethyl 6-(hexahydro-lH-azepin-1-yl)methyleneamino
penicillanate. Examples 2 to 7 illustrate the preparation of compounds other
than the compound of the invention but it will be readily inferred that the
1055929
compound of the invention can be made by the procedures illustrated in Ex-
amples 2 to 5. Likewise, in Example ô formulations (b), (g) and (i) contain
the compound of the invention whereas formulations (a), (c) to (f) and (h)
contain compounds other than the compound of the invention but it will be
readily inferred that the compound of the invention could be substituted for
the other compounds in these formulations.
Example 1
l'-Ethoxycarbonyloxy-ethyl 6-(hexahydro-lH-azepin-l-yl)-methyl-
eneamino penicillanate.
l-Hexamethyleneiminocarboxaldehyde-dimethylacetal (3.1 g) in
chloroform (50 ml) was added dropwise at -30C to a solution of l'-ethoxy-
carbonyloxy-ethyl 6-amino-penicillanate (5 g) and triethylamine (1.9 ml) in
chloroform (150 ml) during 15 minutes. Then the temperature is allowed to
rise to 0 during 30 minutes and the mixture is stirred at 0 for another 60
minutes. Water (120 ml) is added and stirring is continued for 10 minutes.
The water phase is separated and the organic layer is washed with water and
stripped. The residue (5 g) showed a strong IR-absorption band at 1775 cm
(~-lactam ring).
Incubation of the product with human serum at 37 C was found to
cause a rapid formation of 6-(hexahydro-lH-azepin-l-yl)-methyleneamino pen-
icillanic acid.
The 1'-ethoxycarbonyloxy-ethyl 6-aminopenicillanate was prepared
as described in Canadian Patent No. 960,211.
Example 2
By substituting the l'-ethoxycarbonyloxy-ethyl 6-aminopenicillan-
ate in example 1 with l'-acetoxy-ethyl 6-aminopenicillanate and ethoxy-
carbonyloxymethyl 6-amino-penicillanate, l'-acetoxy-ethyl and ethoxycar-
bonyloxymethyl 6-(hexahydro-lH-azepin-l-yl)-methyleneamino penicillanates
respectively were obtained. The compounds showed strong ~-lactam absorption
in IR at 1775 cm and were rapidly hydrolyzed by human serum to the cor-
~055929
responding penicillanic acids.
Example 3
l'-Ethoxycarbonyloxyethyl 6-(piperidyl-2-)-methyleneaminopenicil-
anate.
To phosphorus pentachloride (1.7 g, 0.003 mole) and quinoline (1.8
g, 0.016 mole) in dry methylene chloride (50 ml) 1'-ethoxycarbonyloxy-ethyl
6-phenylacetamido penicillanate (3.2 g, 0.007 mole) was added with stirring
and chilling to -40 C, the reaction was kept in dry inert gas (argon). Af-
ter 1 hour dry methanol (2.24 g) was added dropwise and the temperature was
adjusted to -30 . After 1 hour brine (15 ml) was dropped to the solution
while the temperature was allowed to rise to 0 . After 15 min. the organic
phase was dried and evaporated in vacuo, the residue was triturated with
petroleum ether and dried yielding a crystalline mass (2.8 g, 100%), IR 1790
cm (~-lactam) of l'-ethoxycarbonyloxy ethyl-6-amino penicillanate. To a
solution of this material (2.8 g, 0.007 mole) and triethylamine (o.84 ml,
o.oo6 mole) in chloroform (50 ml) at -50 - -60 N-piperidylchloroformimin-
-ium-chloride (1.1 g, o.oo6 mole) in chloroform (20 ml) was added dropwise.
The mixture was kept under dry argon for 1.5 h during which time the temper-
ature rose to 0 . The solvent was removed in vacuo at 40 and the residue
was slurried with d~y acetone (100 ml) and filtered. The filtrate was con-
centrated in vacuo and the remaining oil was triturated with petroleum ether
until crystallisation, yield 1.2 g, IR-absorption 1760 cm (~-lactam), NMR:
ringlet at 480 cps (methyleneimino), multiplet at 320 cps (5- and 6-position
of penicillin nucleus).
Example 4
l'-Acetoxyethyl 6-(piperidyl-1)-methyleneaminopenicillanate was
prepared as described in Example 3 from l'-acetoxyethyl 6-phenylacetamido
penicillanate (2.94 g, 0.007 mole) and N-piperidylchloroformiminiumchloride
(1.1 g, o.oo6 mole) yielding a half crystalline mass. IR-absorption at 1760
cm (~-lactam).
-- 10 --
lOSS9;~9
Example 5
Ethoxycarbonyloxymethyl 6-(hexahydro-lH-azepin-l-yl)-methylene-
aminopenicillanate was prepared as described in example 3 from ethoxycar-
bonyloxymethyl 6-phenylacetamido penicillanate (3.0 g, 0.008 mole) and hexa-
hydro-lH-azepin-l-ylchloroformiminium chloride (1.15 g, o.oo6 mole) yielding
an oil; IR-absorption 1760 cm (~-lactam).
Example 6
Phenoxycarbonyloxymethyl 6-(ethyl-isopropyl)-methyleneaminopeni-
cillanate was prepared as described in Example 3 from phenoxycarbonyloxy-
methyl 6-phenylacetamido penicillanate (3.4 g, 0.007 mole) and N-ethyl-N-
isopropylchloroformiminium chloride (1.02 g, o.oo6 mole) yielding an oily
product; IR-absorption 1775 cm (~-lactam).
Example 7
Phenoxycarbonyloxymethyl 6-(N,N-dimethyl)-methyleneaminopeni-
cillanate was prepared as described in Example 3 from phenoxycarbonyloxy-
methyl 6-phenylacetamido penicillanate (3.4 g, 0.007 mole) and N,N-dimethyl-
chloroformiminium chloride (0.77 g, o.oo6 mole) yielding a half crystalline
mass; IR-absorption 1775 cm (~-lactam).
Example 8
Pharmaceutical formulations
For preparation of tablets the following compositions were made:
a) l'-Acetoxyethyl 6-hexahydro-lH-azepin-l-(yl)-
-methyleneamino penicillanate325 mg
Starch 100 mg
Magnesium stearate 10 mg
b) l'Ethoxycarbonyloxyethyl 6-hexahydro-lH-azepin-
-l-(yl)-methyleneamino penicillanate 350 mg
Starch 100 mg
Magnesium stearate 10 mg
c) Ethoxycarbonyloxymethyl 6-hexahydro-lH-azepin-
~05S929
-l-(yl)-methyleneamino penicillanate 350 mg
Calcium carbonate 100 mg
Magnesium stearate 10 mg
d) ~-Ethoxycarbonyloxyethyl 6-(piperidyl~l)-methyl-
ideneamino-penicillanate350 mg
Lactose 100 mg
Magnesium stearate 10 mg
e) l',-Acetoxyethyl 6-(piperidyl-1)-methylidene-
amino-penicillanate 300 mg
Calcium carbonate 100 mg
Lactose 100 mg
Magnesium stearate 10 mg
For filling in capsules the following formulations were made:
f) 1'-Acetoxyethyl 6-hexahydro-IH-azepin-l-(yl)-
methyl-ideneamino penicillanate 350 mg
Magnesium stearate 5 mg
g) l'-Ethoxycarbonyloxyethyl 6-hexahydro-lH-
azepin-l-(yl)-methylideneamino penicillanate 350 mg
Lactose 40 mg
Magnesium stearate 5 mg
For oral suspensions the following formulations were prepared:
h) l'-Acetoxyethyl 6-(piperidyl-1)-methylideneamino
penicillanate 35 mg
Aluminium monostearate 50 mg
~ween - 80 ~
Peanut oil ad lO00 mg
i) l'-Ethoxycarbonyloxyethyl 6-hexahydro-lH-
azepin-l-(yl)-methylideneamino penicillan-
ate 36 g
Sodium benzoate o.48 g
- 12 -
~0559;~9
Sodium chloride ~75 g
Flavouring agents 4.7 g
Aerosil 3 g
Antifoam 0.0375 g
AIkali salts of polysaccharide sulphates 4.0 g
Sodium saccharinate 0.4 g
Sorbitol ad 100 g
- 13 -
`
l(~SS9Z9
SUPPLEME~TARY DISCLOSURE
Example 9 Preparation of l'(S)-Ethoxycarbonyloxyethyl 6~(hexahydro-lH-azepin-
l-yl)-methyleneaminopenicillanate hydrochloride
A. Pre~aration of l'(S)-Ethoxycarbonyloxyethyl 6R-amino~enicillanate
hydrochloride used as starting material
A solution of l'(S)-ethoxycarbonyloxyethyl 6-phenylacetamido peni-
cillanate (7.4 g, 0.016 mole) in 10 ml dry ethanol-free chloroform was added
to a stirred mixture of phosphorus pentachloride (3.8 g, 0.018 mole) and
quinoline (4.8 g, 0.037 mole) in 25 ml dry ethanol-free chloroform at -20C
under dry nitrogen. After stirring at this temperature for 1 h, the solution
was cooled to -30C and dry propanol ~12 ml) was added during 20 mins. The
temperature was allowed to rise to -15C during 30 mins, then cold brine
(25 ml) was added with vigorous stirring while the temperature rose to -50C.
The reaction mixture was poured into 50 ml ice-cold ligroin and stirred for
15 mins, then a further 55 ml ice-cold ligroin were added and the mixture
stirred for a further 10 min~. The mixture was then allowed to separate and
the oil-water phase collected and extracted with 30 ml chloroform. The chloro-
form phase was dried at 0C over sodium sulphate. lR (CHC13) showed ~-lactam
(1790 cm~l) and ester (1790 cm~l). NMR (CDC13): C(6)H, lH, d at 5.68 ppm
(J=4.0 Hz); C(s)H, lH, d at 5.20 ppm (J=4.0 Hz).
B. l'(S)-Ethoxycarbonyloxyethyl 6~-(hexahydro-lH-azepin-l-yl)-methyl-
eneaminopenicillanate hydrochloride
To the above-described chloroform solution of l'(S)-ethoxycarbonyl-
oxyethyl 6B-aminopenicillanate hydrochloride cooled to -40C, triethylamine
(5.80 ml, 0.042 mole) was added with stirring. The temperature was allowed
to rise to -25C and then a solution of hexahydro-lH-a7epin-l-ylchloroform-
iminium chloride (3.79 g, 0.021 mole) in 10 ml dry ethanol-free chloroform
was added dropwise. The mixture was then stirred at 0C for 30 mins. After
removal of the solvent under reduced pressure the resulting residue was
slurried with dry acetone (50 ml) and filtered. The filtrate was stripped
- 14 -
lOSS9Z9
of solvent and leached with petroleum ether and the syrupy residue dissolved
by stirring with 10 ml 2-pentanon. The solution was kept at +5C overnight
whereupon the crude product crystallized and was collected by filtration.
The crude product was dissolved in methylene chloride (12 ml) and washed with
cold saturated brine (2x15 ml). After drying the organic phase over sodium
sulphate, the solvent was removed under reduced pressure and the resulting
residue slurried with dry acetone (5 ml) affording the analytically pure
crystalline product, m.p. 147-149C (decomposition). ~a]D = +163.5 (c=l;
96 % ethanol). lR (KBr): 1795 cm~l (B-lactam carbonyl); 1760 cm~l (ester
carbonyl)3 1675 cm~l (-CH=NH-).
A proton NMR spectrum of the product showed only one signal for
the C-3 proton indicating the presence of only one stereoisomer. This was
confirmed by a carbon-13 NMR spectrum in CDC13 since only one signal was seen
for the 2~-methyl carbon at 29.44 ppm (from TMS) whereas a mixture of the two
stereoisomers gave signals for this carbon at 29.51 and 30.50 ppm.
Found: C 50.21; H 6.62; Cl 7.55; N 8.89; S 6.56; Calc. for
C20H32ClN306S. C50.25; H 6.75; Cl 7.42; N 8.79; S 6.71.
