Process for the preparation of cephem ester prodrugs.

OBJECT OF THE INVENTION PROCESS FOR PRODUCING ESTERS CEFEM EQUALS C1 or organic, and where the group hydroxylimino is present in the FORMLESS, wherein IS A compound of formula II wherein R2 is a group PROTECTED cleavable by hydrolyzing acidic, with a disulphide BIS (benzothiazol OXY, acetoxy, nitro, amino, carboxy or group sulfo, and triphenylphosphine in an inert solvent, in the presence of tertiary amine is transformed into a compound of formula V wherein R2 and R3 are as defined above, CONTINUATION this compound is reacted with an ester 7 LA FORMULA III wherein R1 has the meaning given ABOVE, IN inert organic solvents or dipolar aprotic at temperatures between 0 ( GRADES) Y + 80 (degrees) and Compound PROTECTED oxime formula IV wherein R1 and R2 have the meanings FOREGOING, AND WHERE THE GROUP OX PROTECTED IMA is present in the shapeless TREATED WITH ACID OR INORGANIC aliphatic or aromatic sulfonic acids ORGANIC SOLVENT at temperatures between +20 (degrees) CY +110 (degrees) C, UNDER THE FORMATION OF COMPOUND OF FORMULA I.