Patent ID: 6696568
Filing Date: 2004-02-24
Classification: C07D,C07F

Abstract:
A process for the preparation of a compound of the formula [I]: stereoisomers of the compound of formula [I]or acid addition salts thereof,wherein R1 is selected from the group consisting of alkyl having from 1 to 4 carbon atoms, cyclohexyl, phenyl, and dimethylamino alkyl group â€”(CH2)nNMe2 in which n is an integer from 2 to 6, R2 is selected from the group consisting of hydrogen, alkyl having from 1 to 4 carbon atoms, cyclohexyl, phenyl, dimethylamino alkyl group â€”(CH2)nNMe2 in which n is an integer from 2 to 6, pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, thiazolyl and thiadiazolyl, R3 represents a hydrocarbon group having from 1 to 4 carbon atoms, and R4 is selected from the group consisting of hydrogen, halogen, methylthio and phenylthio group; which process comprises silylating with a silylation agent a compound represented by the formula [2]: stereoisomers of the compound represented by formula [2] or metal or ammonium salts or acid addition salts thereof,wherein R2, R3 and R4 are as defined above, and reacting the resultant product with a compound represented by the formula [5]: R1â€”N&boxH;C&boxH;O â€ƒâ€ƒ[5]wherein R1 is as defined above, followed by desilylation.