abstract |
1,2,5,7-tetrahydro-7-oxo- Alpha -phthalimido-4H-furo(3,4d)(1,3)thiazine-2-acetic acid esters which are useful in the synthesis of cephalosporins are prepared starting with gamma , gamma ''-dihydroxyvaline lactone hydrochloride I and phthalimidomalonaldehydic esters II. |