| abstract |
1437221 Cephalosphorin silyl esters E R SQIBB & SONS Inc 4 July 1973 [4 Aug 1972] 31882/73 Heading C3S [Also in Division C2] The novel cephem compound of formula wherein R is a trimethylsilyl group, R 1 is a group -CH 2 -CH = CH 2 , R 2 is H, R 3 is ethyl and X is H, is prepared by reacting trimethylsilyl ester of 7-amino-3-desacetoxycephalosporanic acid with a cyanomethylthioacetyl chloride of formula wherein R 1 , R 2 and R 3 are as defined above and R 5 is chlorine. |