BETA-LACTIAN ANTIBIOTICS AND PROCESS FOR PREPARATION THEREOF

摘要

1-Carba(-ditha)-3-cephem-4-carboxylic acid esters of formula (I) and their acid addn. salts are prepd. by cyclization of a cpd. of formula (II) in the presence fo Rh catalyst. In the formulas, R1 is a protecting gp.; R2= H, a protecting gp. or COR3; R3= C1-6 alkyl, Ar, CH2(Z)mAr or OR3≰C; Ar= phenyl obt. substd. by 1 or 2 of C1-4 alkyl, C1-4 alkoxy and halogen; Z= O or S; m= 0 or 1; R3≰C= C1-4 alkyl, C5-7 cycloalkyl, benzyl, nitrobenzyl, methoxybenzyl or halobenyl. (I) are sueful as antibiotic intermediates.