| 摘要 |
1. A process for the preparation of a compound of formula (I) by the reaction of a compound of formula (II) with a compound of formula (III), according to the reaction scheme indicated below: wherein R1 is lower alkyl; R2 is lower alkyl; or phenyl optionally substituted by from one to five groups which may be the same or different selected from lower alkyl, lower haloalkyl, halogen and -SR4; R3 is halogen, lower alkyl, lower haloalkyl, lower alkoxy, lower haloalkoxy, -S-alkyl, cycloalkyl having from 3 to 7 carbon atoms in the ring, alkenyl or alkynyl having from 3 to 7 carbon atoms, or -(CR5R6)q-SR2, wherein q is one or two; R4 is lower alkyl; R5 and R6 independently represent hydrogen, lower alkyl or lower haloalkyl, and n is zero or an integer from one to three, and wherein the reaction is performed with continuous distillation of the alcohol R1-OH formed in the course of the reaction, at atmospheric pressure or under reduced pressure, and where "lower" means radical, comprising at least one hydrocarbon chain. 2. A process according to claim 1 in which the reaction is performed in an aprotic solvent and at a temperature of from 0 degree C to the boiling point of the solvent, preferably between 0 degree C and 100 degree C. 3. A process according to claim 1 or 2 in the presence of a strong base, preferably an alkoxide of an alkali or alkaline earth metal or a metal hydride. 4. A process according to claim 1, 2 or 3, wherein the reaction is performed from 1 to 20% below atmospheric pressure. |
