Useful intermediates for preparing a 1-dethia-1-oxacephalosporin and represented by the following formula: ##STR1## (wherein R is a monovalent group resulting from the elimination of the carbonyl function of an acyl group derived from a carboxylic or carbonic acid; COB is carboxy or protected carboxy; and X is hydrogen or a nucleophilic group) are prepared from the corresponding penicillin 1-oxides of the following formula: ##STR2## (wherein R, COB, and X are as defined above) by heating, if required in the presence of the desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.
用于制备1-去
硫基-1-氧代
头孢菌素的有用中间体,其
化学式如下:##STR1##(其中R是由
羧酸或
碳酸衍生的酰基的羰基功能消除后得到的一价基团;COB是羧基或保护羧基;X是氢或亲核基团)。通过加热相应的
青霉素1-氧化物(其
化学式如下:##STR2##)(其中R,COB和X如上所定义)制备,如有必要,在去
硫化试剂的存在下进行加热,或在适当的亲核取代条件下交换X基团。