GB1413070A — Process for the production of - norfenfluramine and - fenfluramine and salts thereof

USPTO Abstract

1413070 (-)-Norfenfluramine BEECHAM GROUP Ltd 18 July 1974 [27 July 1973] 35923/73 Heading C2C (-)-Norfenfluramine or a salt thereof may be prepared by hydrogenating the novel compound of Formula (I) or a salt thereof: where R is a phenyl group, optionally substituted in the meta- or para-positions by a non- reactive group that does not interfere with the hydrogenation, the carbon atom marked with one asterisk has the same configuration as (-)-norfenfluramine and the carbon atom marked with two asterisks has the configuration found in (+ )-a-methylbenzylamine. The compound of Formula (I) may be prepared by reducing a compound of Formula II or a salt thereof: which may itself be prepared by reacting l-(mtrifluoromethylphenyl)propan-2-one with (+ )- α-methylbenzylamine. (-)-Fenfluramine may be prepared by the acetylation of (-)-norfenfluramine in conventional manner followed by reduction of the acetyl group to an ethyl group.