Patent ID: 6437142
Filing Date: 2002-08-20
Classification: C07B,C07C,C07F,C12P,Y02P

Abstract:
A process for preparing a compound of the formula: wherein R1, R2 are each independently lower alkyl or lower perfluoroalkyl and Y is Si(C1-4-alkyl)3; which comprises:a) reacting a compound of the formula: â€ƒwherein R1, R2 and Y are as above; with Me3SiCH2CO2R5, Ph3P&boxH;CHâ€”CO2R5 or (EtO)2P(O)CH2CO2R5 wherein R5 is lower alkyl; to obtain the compound of the formula: â€ƒwherein R1, R2, R5 and Y are as above; b) reducing the ester group to obtain the hydroxy derivative of the compound of formula (10); c) coupling the compound obtained in step (b) with 5-mercapto-1-phenyl-tetrazole or 2-mercapto-benzothiazole to obtain the compound of the formula: â€ƒwherein R1, R2 and Y are as above; and d) oxidizing the sulfanyl group of the compound of the formula 11 to obtain the compound of formula IIIa.