| 摘要 |
This invention relates to a novel process for the preparation of 3-cyclic-ether-substituted cephalosporins of formula I wherein the group CO2R<1 >is a carboxylic acid or a carboxylate salt and R<2 >has the formula: wherein A<1 >is selected from the group consisting of C6-10aryl, C1-10heteroaryl and C1-10heterocyclyl; A<2 >is selected from the group consisting of hydrogen, C1-6alkyl, C3-10cycloalkyl, C6-10aryl, C1-6alkyl(CO)(C1-6)alkyl-O-, HO(CO)(C1-6)alkyl, mono-(C6-10aryl)(C1-6alkyl), di-(C6-10aryl)(C1-6alkyl) and tri-(C6-10aryl)(C1-6alkyl); from a zwitterionic compound of formula II; or from a compound of formula V: wherein R<2 >is as defined above and R<3 >is para-nitrobenzyl or allyl. The invention also relates to the preparation of the above compounds of formulae II and V.
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