ESTERS OF '-SUBSTITUTED AMIDINOPENICILLANIC ACIDS

The present invention relates to new penicillanic acid derivatives which are effective in treatment of infectious diseases caused by bacterial microorganisms and to methods for their preparation. More precisely this invention relates to new esters of amidinopenicillanic acids of the formula: I and therapeutically acceptable salts thereof, wherein R1 and R2, which are the same or different, are alkyl groups containing from 1 to 10 carbon atoms R1 and R2 together with the adjacent nitrogen atom form a heterocyclic ring system; R3 is selected from the group consisting of and in which radicals R4 is selected from the group consisting of alkyl groups containing from 1 to 8 carbon atoms, or phenyl, R5 is selected from the group consisting of hydrogen, methyl and ethyl, with the proviso that when R1 and R2 together with the adjacent nitrogen atom form a hexahydro-1H-azepine ring R3 is and R5 is methyl R4 is not ethyl. The compounds of this invention are of value in the treatment of infectious diseases in man or animals caused by bacterial organisms. They are prepared according to known methods for the preparation of penicillin derivatives.