NEW MATERIAL: A compd. of formula I (R1 is a 1-8C alkyl or a 6-10C alkyl; R2 is H, a 1-8C alkyl or a 2-8C acyl; R3 is H, a 1-8C thioalkyl, a 6-10C thioryl or 5- or 6-membered thioheteroaryl; R4 is H, an alkali metal salt or a biologically active ester).
EXAMPLE: (±)-3S-acetoxyacetoamide-4R-(1-t-butyldiphenylsilyloxy-2S-propyl)-1-p- methoxyphenyl-azetidine-2-on.
USE: An antibiotic effective to Gram-positive and-negative bacteria.
PROCESS: A compd. of formula II as a starting substance is used and it is acylated with acetoxyacetyl chloride at 0°C for 1 hr and then, is reacted successively to obtain an intermediate of formula III and further, the carboxyl group at 6-position of carbapenem is deprotected and the protected group is substd. with H, etc.
FURANKU PII DEINITSUNO
TOMASU ENU ZARUTSUMAN
