Useful intermediates, 7α-acylamino-3-(oxo or exomethylene)-1-dethia-1-oxacepham-4a-carboxylates, are produced by the intramolecular carbenoid insertion of a 2-diazo-3-(oxo or exomethylene)-4-(3α-acylamino-2-oxoazetidin-4β-yl)oxybutyrate prepared in several steps from the corresponding oxazolinoazetidinone and diketone.
有用的中间体 7α-acylamino-3-(oxo or exomethylene)-1-dethia-1-oxacepham-4a-carboxylates 是通过 2-重氮-3-(氧代或外亚甲基)-4-(3α-acylamino-2-oxoazetidin-4β-yl)氧
丁酸酯的分子内类羰基插入物,由相应的
噁唑烷氮杂
环丁酮和二酮经过几个步骤制备而成。