Thiazolinoazetidinone derivative and process for preparing 2-exo-methylene-penam derivative thereform

摘要

The present invention provides a thiazolinoazetidinone derivative represented by the formula wherein R<1> is phenyl having or not having substituent(s), methyl having or not having substituent(s) or group, R<3> being phenyl having or not having substituent(s), and R<2> is a hydrogen atom or carboxylic acid protective group, and a process for preparing the same. The present invention further provides a process for preparing a 2-exo-methylenepenam derivative characterized by hydrolyzing the thiazoline ring of a thiazolinoazetidinone derivative of the above formula (1) to effect recyclization and obtain a 2-exo-methylenepenam derivative represented by the formula wherein R<1> and R<2> are as defined above. o