PROCESS FOR THE PREPARATION OF SPIRO-[CIS-4-(BETA-HYDROXYETHYLOXY)CYCLOHEXANE-(3H) INDOL)-2'(1'H)-ONE DERIVATIVES

摘要

The invention relates to a process for the preparation of spiro[cis-4-(.beta .- hydroxyethyloxy) cyclohexane- [3H] -2'[1'H]-one derivatives of the formula ( I) wherein R1 and R2 stand independently from each other for hydrogen, C1-4alky l, C1-4alkoxy, C1-4alkylthio, C1-4polyfluroalkyl, C1-4polyfluroalkoxy, C3- 7cycloalkyloxy, C3-7cycloakylthio, phenoxy, benzyloxy or nitro group by reduction of a dispiro [(1,3- dioxolane)-2,4'- cyclohexane-1', 3"-[3H]indol] - 2"[1"H]- one derivative of general formula (II), wherein R1 and R2 are as defined above, which comprises carrying out the reduction (a) with sodium cyanoborohydride in the presence of a Lewis acid, or (b) with sodium borohydride in the presence of a strong acid.