4-(3-Phenyl-5-methyl)-isoxazolyl-carbonyl-penicillin prepn - by reaction of 6-APA with tetrolic acid chloride and then with phenyl nitrile oxide

摘要

Title cpds. of formula (I): (where R1 and R2 are H, halo, lower alkoxy or pseudo-halo); and salts with alkali(ne earth) metals, are prepd. by reacting 6-APA (II) with tetronic acid chloride (C(COCI)triple bondC.CH3) under acylating conditions to give an inter. (II; -NH2 is C(triple bondC)-CO-NH-) which is reacted at low temp. in the presence of N-ethyl piperidine with a cpd. (III) to give title prodt. (I) are antibiotics effective against penicillin-resistant strains of bacteria and are stable to penicillinase.