PRODUCTION OF 3-EXOMETHYLENE CEPHAM COMPOUND

摘要

PURPOSE:To obtain a 3-exomethylene cepham compound which is an important intermediate for cepham-based antibiotics in high reaction selectivity and high yield by irradiating a substituted dithioazetidinone compound with ultraviolet rays in the presence of an active hydrogen-containing compound in an inert solvent. CONSTITUTION:The method for producing (C) a 3-exomethylenecepham compound of formula II is to irradiate (A) a 4-substituted dithio-2-azetidinone compound of formula I (A1 is H or an acyl; A2 is H or an amino-protecting group; Y is H or methoxy; Z is hydroxyl group or a group capable of forming a protected carboxyl together with carbonyl; R is an organic group) with ultraviolet rays having preferably 280-400nm wavelength in an inert solvent in the presence of (B) a compound of the formula R<1>-H (R<1> is an organic group) having <=350KJ/mol bonding and dissociating energy between R<1> and H and having an active hydrogen. Furthermore, the component A is preferably contained in an amount of 0.1mmol/L to 1mol/L in the inert solvent.