6-[D-.alpha.-(Coumarin-3-carboxamido)arylacetamido]-penicillanic acids or salts

This disclosure describes compounds of the class of 6-[D-.alpha.-(benzocoumarin-3-carboxamido)phenylacetamido] penicillanic acids which possess antimicrobial activity.

BRIEF SUMMARY OF THE INVENTION 
This invention relates to new derivatives of 6-aminopenicillanic acid and, 
more particularly, is concerned with novel compounds which may be 
represented by the following structural formula: 
##STR1## 
wherein R.sub.1 is hydrogen or hydroxy; R.sub.2 and R.sub.3 taken 
together, R.sub.3 and R.sub.4 taken together, and R.sub.4 and R.sub.5 
taken together are each butadienylene; and M is hydrogen or a 
pharmaceutically acceptable non-toxic cation. 
DETAILED DESCRIPTION OF THE INVENTION 
The pharmacologically acceptable cations embraced by M in the above general 
formula include, for example, the non-toxic metal cations such as the 
sodium ion, potassium ion, calcium ion, magnesium ion, as well as the 
organic amine cations such as the tri(lower alkyl)amine cations (e.g., 
triethylamine), procaine, and the like. 
The novel compounds of the present invention may be readily prepared by 
condensing an ampicillin derivative of the formula: 
##STR2## 
wherein R.sub.1 and M are as hereinabove defined with a 
benzocoumarin-3-carboxylic acid derivative of the formula: 
##STR3## 
wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as hereinabove defined 
and X is chloro or bromo as in an acid halide, or the moiety 
--O--CO--OC.sub.2 H.sub.5 as in a mixed anhydride from ethyl 
chloroformate, or the moiety --O--C(.dbd.N-cyclohexyl)NH-cyclohexyl as in 
a dicyclohexylcarbodiimide mediated reaction, or an azide function, or an 
azolide formed from carbonyldiimidazole. This acylation of the ampicillin 
derivative is best performed in an inert solvent such as tetrahydrofuran, 
dioxane, methylene chloride or chloroform (or mixtures thereof) at from 
ice bath temperature (about 0.degree. C.) to room temperature (about 
25.degree. C.). The reaction is preferably carried out in the presence of 
an acid acceptor such as N-methylmorpholine, triethylamine, or soda ash 
and over a period of a few hours or more. The acylating agents may be 
prepared by methods well known in the art from the corresponding acid (X 
is hydroxy). Thus, an acid may be treated with a thionyl halide or oxalyl 
halide, if desired, in the presence of dimethylformamide, to yield the 
corresponding acyl halides (X is chloro or bromo), which can be converted 
to the acyl azides (X is N.sub.3) by treatment with sodium azide. 
The novel compounds of the present invention are biologically active and 
have been found to possess antibacterial activity. As indicated, they are 
useful antimicrobial agents and have broad-spectrum antimicrobial activity 
in vitro against standard laboratory microorganisms used to screen for 
activity against pathogens. The antibacterial spectrum of typical 
compounds of the present invention, representing the concentration 
required to inhibit the growth of various typical bacteria, was determined 
in a standard manner by the agar-dilution streak-plate technique. A Steers 
multiple inocula replicator was employed with incubation at 37.degree. C. 
for 18 hours in conventional nutrient agar. The results are set forth in 
Table I below expressed as the minimal inhibitory concentration in 
micrograms per milliliter.

The invention will be described in conjunction with the following specific 
examples. 
EXAMPLE 1 
6-[D-.alpha.-(5,6-Benzocoumarin-3-carboxamido)phenylacetamido]penicillanic 
acid 
To a suspension of 483 mg. of 5,6-benzocoumarin-3-carboxylic acid in 45 ml. 
of dioxane and 10 ml. of acetone is added 0.282 ml. of triethylamine. The 
mixture is cooled and stirred in an ice bath and 0.194 ml. of ethyl 
chloroformate is added dropwise over 10 minutes. Stirring and cooling is 
continued another 45 minutes. Then 0.281 ml. of triethyl amine and 807 mg. 
of ampicillin trihydrate are added. Stirring and cooling is continued 
another hour. A chilled mixture of 3 ml. of saturated sodium bicarbonate 
solution and 35 ml. of water is added and the reaction mixture is shaken 
with 100 ml. of ethyl acetate. The mixture is filtered to remove suspended 
solids. The aqueous layer is acidified, with cooling, with 6 N 
hydrochloric acid to pH 2 and then extracted with 100 ml., then 50 ml. of 
ethyl acetate. The combined ethyl acetate extracts are washed with 25 ml. 
of water, dried over magnesium sulfate and evaporated to a solid. 
Trituration with ether and filtration gives the desired product, i.r. 
5.4.mu. (.beta. lactam). 
EXAMPLE 2 
6-[D-.alpha.-(5,6-Benzocoumarin-3-carboxamido)-p-hydroxyphenylacetamido]pen 
icillanic acid 
To a suspension of 483 mg. of 5,6-benzocoumarin-3-carboxylic acid and 0.225 
ml. of N-methylmorpholine in 25 ml. of dioxane and 25 ml. of methylene 
chloride, cooled to -10.degree. to -15.degree. C. in an ice-methanol bath, 
is added 0.192 ml. of ethyl chloroformate dropwise over several minutes. 
After an additional 25 minutes of stirring and cooling, 0.223 ml. of 
N-methylmorpholine and 770 mg. of amoxicillin are added. The mixture is 
stirred in an ordinary ice bath for one hour. Then a cold mixture of 20 
ml. of dioxane, 10 ml. of acetone, 35 ml. of water and 3 ml. of saturated 
sodium bicarbonate is added. Workup is done as described in Example 1 
giving the desired product i.r. 5.65.mu. (.beta. lactam). 
TABLE I 
__________________________________________________________________________ 
Pseudomonas 
Klebsiella 
Enterobacter 
Proteus 
Protues 
Escherechia 
Staphylococcus 
aeruginosa 
pneumoniae 
cloacae 
mirabills 
morganii 
coli aureus 
Compound USC 7613 
MA 75-2 
OSU 75-2 
OSU 75-3 
K 72 CU 75-1 
OSU 
__________________________________________________________________________ 
75-2 
6-]D-.alpha.-(5,6-Benzocouma- 
rin-3-carboxamido)phen- 
2 16 16 2 32 4 0.12 
ylacetamido]penicillanic 
acid 
6-[D-.alpha.-(5,6-Benzocouma- 
rin-3-carboxamido)-p- 
2 64 64 4 64 16 0.5 
hydroxyphenylaceta- 
mido]penicillanic acid 
6-[D-.alpha.-(6,7-Benzocoumar- 
in-3-carboxamido)-phen- 
1 8 4 0.5 16 16 .ltoreq.0.06 
acid 
6-[D-.alpha.-(7,8-Benzocou- 
marin-3-carboxamido)- 
4 16 16 1 16 8 0.5 
phenylacetamido]peni- 
cillanic acid 
Carbenicillin 32 &gt;128 32 1 128 8 0.5 
Ampicillin &gt;128 16 &gt;128 0.25 &gt;128 1 0.12 
6-[D-.alpha.-(7,8-Benzocou- 
marin-3-carboxamido)- 
phenylacetamid]peni- 
cillanic acid 2 16 8 4 16 8 0.12 
__________________________________________________________________________ 
EXAMPLE 3 
6-[D-.alpha.-(6,7-Benzocoumarin-3-carboxamido)phenylacetamido]penicillanic 
acid 
This compound is prepared similarly to the 5,6-benzo analog of Example 1. 
Thus, 336 mg. of carboxylic acid [T. Boehm and E. Profft, Arch. Pharm., 
269, 25 (1931)] gives the desired compound, i.r. 5.67.mu. (.beta. lactam). 
EXAMPLE 4 
6-[D-.alpha.-(7,8-Benzocoumarin-3-carboxamido)phenylacetamido]penicillanic 
acid 
This compound is prepared as described in Example 1, i.r. 5.65.mu. (.beta. 
lactam). The acid is prepared after F. D. Cramer and H. Winderl, Chem. 
Ber., 89, 354 (1956).