| 摘要 |
NEW MATERIAL:Compounds of formula 1 (R<1> is H, lower alkyl; lower alkoxy, lower hydroxyalkyl; R<2> is H, lower alkyl; R<3> is H, amino-protecting group; A is lower alkyl with branched chains; R<4> is H, carboxyl-protecting group) and their pharmacologically permissible salts. EXAMPLE:2-(2-Amino-1-methylethylthio)penem-3-carboxylic acid. USE:Antibacterial and its synthetic intermediate: they are effective against a wide range of pathogenic bacteria including gram-positive and -negative bacteria. PREPARATION:A compound of formula 6 (R<7> is lower alkyl, lower alkoxy; R<8> is amino-protecting group; R<9> is carboxyl-protecting group; Z<+> is trisubstituted phosphonio, diesterified phosphono with a cation) is heated to form the compound of formula 7, which is when necessary, subjected to the removal of protecting groups or the conversion of substituted groups to produce the compound of formula 1. |
