PROCESS FOR THE PREPARATION OF OPTICALLY UNIFORM AZETIDINONES

摘要

1. A process for the manufacture of optically uniform azetidinones of the general formula see diagramm : EP0138113,P5,F1 wherein R signifies benzyl, beta-(trimethylsilyl)-lower alkyl or beta-halo-lower alkyl, R**1 signifies a readily cleavable protecting group from the group consisting of benzyl, 2,4- or 3,4-di(lower alkoxy)benzyl, di[4-(lower alkoxy)phenyl]methyl, 4-(lower alkoxy)phenyl, lower 2-alkenyl and the group of the formula -CH2 -CH(OR**5)2 (a) or see diagramm : EP0138113,P5,F2 in which R**5 signifies lower alkyl and n signifies the number 0 or 1, R**2 signifies lower alkyl, phenyl-lower alkyl or lower alkoxyalkyl and R**3 signifies lower alkyl or phenyl-lower alkyl or R**2 and R**3 together with the centre of chirality and the oxygen atom signify a 5 or 6-membered 0-heterocycle which optionally contains a further oxygen atom not directly linked with the centre of chirality and which is optionally substituted by lower alkyl, lower alkoxy, oxo or spirocyclo-lower alkyl, and the residues denoted by lower have up to eight carbon atoms, characterized by reacting an alkali metal salt of a carboxylic acid of the general formula ROCONHCH2 COOH wherein R has the above significance, with an optically uniform compound of the general formula see diagramm : EP0138113,P6,F3 wherein R**1, R**2 and R**3 have the above significance, in the presence of a base and a sulphonic acid chloride of the general formula R**4-SO2 -Cl wherein R**4 signifies phenyl, lower alkylphenyl, halophenyl, lower alkyl or halo-lower alkyl, whereby the reaction is carried out in an anhydrous inert organic solvent at a temperature in the range of about -30 degrees C to about 50 degrees C.