Certain phosphinic acid derivatives having antibacterial activity

A compound of the formula:

• ##STR53## wherein:
• R.sub.1 is
• H, CH.sub.3 ;
• R.sub.2 is
• (a) hydrogen,
• (b) C.sub.1 -C.sub.12 linear or branched alkyl;
• (c) C.sub.2 -C.sub.12 linear or branched monoalkenyl;
• or
• (d) C.sub.7 -C.sub.20 aralkyl, wherein the alkyl chain is linear or branched C.sub.1 -C.sub.8 ;
• wherein said above values for R.sub.2 can be substituted by a substituent selected from the group consisting of:
• halo, hydroxy, carboxy, C.sub.1 -C.sub.4 alkoxycarbonyl, C.sub.7 -C.sub.16 arylalkoxycarbonyl, C.sub.3 -C.sub.7 cycloalkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.6 -C.sub.12 aryloxy, amino, mono- or di-C.sub.1 -C.sub.8 alkylamino, thio, C.sub.1 -C.sub.4 alkylthio, C.sub.6 -C.sub.12 arylthio, C.sub.7 -C.sub.16 aralkylthio, or the radical --S--(CH.sub.2).sub.n --CH(NH.sub.2)COOH, where n=1-2;
• with the proviso that R.sub.2 is at least C.sub.2 alkyl if substituted by one of the above-defined thio groups, and wherein the aryl can be further substituted by C.sub.1 -C.sub.4 linear or branched alkyl, trihalomethyl, nitro, cyano or sulfonamido, halo;
• R.sub.3 and R.sub.4 are hydrogen, C.sub.1 -C.sub.4 alkyl, aryl selected from the group consisting of phenyl, naphthyl and biphenyl or aralkyl having one to eight carbon atoms in the alkyl portion and an aryl portion selected from the group consisting of phenyl, naphthyl or biphenyl;
• and including steroisomers and racemates thereof.