PROCESS FOR THE PREPARATION OF RETIGABINE OF THE FORMULA I AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF

摘要

The invention relates to process for the preparation of 2-amino-4-(4- fluorobenzylamino)-l-ethoxycarbonylaminobenzene generically known as Retigabine of the formula (I) and its pharmaceutically acceptable salts e.g. Formula IA, particularly to the modification over the prior art processes-I and II disclosed therein in US5384330. The modifications are depicted in the scheme I and scheme II respectively. Disclosed herein are also the novel processes for the preparation of intermediates of formulae M, N and O of the process-I and of formulae R, S, T of process-II, those are used for preparation of Retigabine of the formula I and its pharmaceutically acceptable salts thereof.