Of retigabine and wherein the intermediate preparation method (by machine translation)
The invention relates to the medicine synthesis field and in particular relates to a preparation method of retigabine and an intermediate thereof. The method specifically comprises the following steps of: (1) preparing a compound with a structure of formula (RET25) by the compound with the structure of formula (RET20) and 4-fluorobenzaldehyde under the action of p-toluene sulfonic acid; (2) preparing the compound with the structure of formula (RET30) by the compound with the structure of formula (RET25) through sodium borohydride reduction; and (3) preparing the retigabine by the compound with the structure of the formula (RET30) through raney nickel hydrogenation reduction. The total impurity content of the retigabine obtained by the preparation method disclosed by the invention is less than 0.16% in terms of area percentage unit of HPLC (High Performance Liquid Chromatography).
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Page/Page column 0064-0066
(2020/05/05)
PROCESS FOR THE PREPARATION OF RETIGABINE OF THE FORMULA I AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF
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.
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(2013/03/26)
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