| abstract |
NEW MATERIAL:A compound of formula I (R 1 is H, alkyl, alkoxyl, etc.; R 2 is H, alkyl, aralkyl, etc. optionally substituted by halogen; R 3 is H or a protecting group of the carboxyl group; A is alkylene) and a pharamcologically acceptable salt thereof. n EXAMPLE: 2-(2-Oxopropylthio)penem-3-carboxylic acid. n USE: An antimicrobial agent and a synthetic intermediate therefor effective against a wide range of pathogenic germs including Gram-positive and Gram-negative bacteria. n PROCESS: A compound of formula II (R 5 is H, alkyl, etc.; R 6 is a protecting group of the carboxyl group; R 7 is lower alkyl) is treated with a base and then reacted with CS 2 and further with a compound of formula III (X is halogen; R a 2 is a part of R 2 ) to give a compound of formula IV, which is then halogenated to give a compound of formula V (Y is halogen) and then cyclized with a base. The protecting group is removed if necessary to afford the compound of formula I. n COPYRIGHT: (C)1981,JPO&Japio |