PROCESS FOR THE PREPARATION OF 3,3-DISUBSTITUTED PIPERIDINES

摘要

A process for preparing a compound of formula (I), wherein R1 represents hydrogen or a protecting group; and R2 represents hydrogen or benzoyl optionally substituted in the phenyl moiety with halogen, methyl or C1-4 alkoxy; which process comprises cyclising a compound of formula (II), wherein R1 is as defined in relation to (I), to provide a cyclic lactam of formula (III), wherein R1 is as defined in relation to (I); reducing the compound of formula (III) so formed to provide a compound of formula (I) wherein R2 represents hydrogen; and thereafter carrying out one or more of the following optional steps: (a) N-acylating the compound of formula (I) wherein R2 represents hydrogen to provide a compound of formula (I) wherein R2 represents benzoyl wherein the phenyl moiety is optionally substituted with halogen, methyl or C1-4 alkoxy; and (b) removing any protecting group.