GB583221A - Improvements in the manufacture of mepacrine hydrochloride - Google Patents

Abstract

Mepacrine Hydroxhloride, i.e. the dihydrate of 2-methoxy-6-chloro-9-(41-diethylamino-11 -methylbutylamino)-acridine dihydrochloride is obtained by adding hydrogen chloride to mepacrine base in aqueous acetic or formic acid solution, whereby the Mepacrine Hydrochloride is precipitated. Advantaneously, the quantities of the starting-materials are so adjusted that the concentrations of the components in the final liquor from which the precipitation takes place are: mepacrine (calculated as base) 5 to 20 per cent, free hydrochloric acid 2.5 to 10 per cent, acetic acid 10 to 20 per cent (or formic acid 5 to 10 per cent), these percentages being calculated weight for weight of the total liquor obtained when hydrochloric acid is rapidly added to the slowly stirred mepacrine acetate (or formate) solution at about 25 DEG C. In examples, Mepacrine Hydrochloride is obtained by: (1) preparing mepacrine base by the reaction described in example 2 of Specification 583,220, treating the reaction mass with a mixture of benzene and aqueous 15 per cent caustic soda solution and extracting the mepacrine as acetate from the benzene layer by treatment with aqueous 20 per cent acetic acid; thereafter the aqueous mepacrine acetate is rapidly treated with concentrated hydrochloric acid at 25 DEG C. to precipitate Mepacrine Hydrochloride; (2) extracting the Mepacrine as formate from the benzene solution of mepacrine base, prepared as in (1), by treatment with aqueous 15 per cent formic acid and adding concentrated hydrochloric acid as in (1) to the aqueous mepacrine formate. Specification 363,392 also is referred to.