ES278136A1 - A procedure for preparing yohimbine alkaloid derivatives (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

A method for preparing yohimbine alkaloid derivatives that have no unsaturation except in rings A and B and having a pyrazole unit or a heterocyclic unit, of isoxazole welded to ring E, in which the carbon atom C17 of the ring E and a contiguous carbon atom of the ring E form part of the heterocycle, which heterocycle may be substituted by lower alkyl, aryl, carboalkoxy and/or trimethoxybenzoyl groups and by their pharmaceutically acceptable acid addition salts, characterized in that: (a) it reacts the corresponding yohimbine that has the following configuration in the E ring: ** (See formula) ** where R, R1 and R2 are (1) hydrogen atoms or lower alkoxy-oxalyl groups, or are (2) hydroxymethylene or carbonyl oxygen groups (in which case the hydrogen atom of the same carbon atom of the E ring is missing) with the provided that one of the substituents is carboxylic oxygen, another substituent is hydrogen and R1 can not be hydrogen, with an amino derivative of the formula: A-NH2 II wherein A is -CH, -NH2, -NHaryl, -NH-lower alkyl, and (b), if desired, when A is -NH2, the product of operation (a) is treated with a lower alkylating agent or with a group capable of introducing the trimethoxybenzoyl group to introduce the lower alkyl substituent or trimethoxybenzoyl in the heterocyclic group and (c), further, if desired, the pharmaceutically acceptable salts of the above are prepared. (Machine-translation by Google Translate, not legally binding)