Preparation of 3-hydroxymethyl cethalosporanic acid and novel process for synthesizing 7 beta-amino-3-non-cephem-4-carboxylic acid using the intermediate

The invention discloses a preparation method for synthesizing an intermediate 7beta-(alkanoylamino)-3-hydroxymethylcephem-4-carboxylic acid of 7beta-amino-3-nor-cephem-4-carboxylic acid, the intermediate has a structural formula (see the right formula); and the invention further discloses a new process for synthesizing the 7beta-amino-3-nor-cephem-4-carboxylic acid from the 7beta-(alkanoylamino)-3-hydroxymethylcephem-4-carboxylic acid. In the synthetic method, 7-ACA is taken as a raw material and the obtained intermediate can be used for rebuilding a plurality of cephalosporin nucleus. The process route is characterized by mild reaction conditions, convenient operation, reliable product purity and high yield, and the method is favorable for large-scale industrialized production.