Patent ID: 6469176
Filing Date: 2002-10-22
Classification: C07C,C07D

Abstract:
A process for preparing a (dihydro)isoxazole of formula I whereinR1 is hydrogen, C1-C6-alkyl, R2 is hydrogen, C1-C6-alkyl, R3, R4, R5 are each hydrogen, C1-C6-alkyl, or R4 and R5 together form a bond, R6 is a heterocyclic ring, n is 0, 1 or 2; which comprises preparing an intermediate of formula VI and subsequently introducing the radical C(O)â€”R6 and converting the NH2 group into the S(O)nR2 radical by a reaction sequence comprisinga halogenation reaction to replace the hydrogen in ortho position to R1 by a halogen radical, a thioalkylation reaction to replace the NH2 group by an Sâ€”R2 radical, optionally an oxydation reaction to convert the Sâ€”R2 radical into the S(O)nR2 radical wherein n denotes 1 or 2, and an acylation reaction to replace the halogen radical in ortho position to R1 by the radical C(O)â€”R6, to give the (dihydro)isoxazole of formula I,and which further comprises preparing a (dihydro)isoxazole of formula V by reacting an oxime of formula III with a compound of formula IV in the presence of a base.