Syntheses of long-chain acids. Part IX. Docosa-3,9,15- and -5,11,17-triynoic acids and eicosa-5,11,14-triynoic acid

Abstract

The acids named in the title, and also hexadeca-3,9-diynoic and eicosa-7,13-diynoic acids, which all contain acetylenic groups separated by a tetramethylene chain, have been synthesised. The methods employed involved alkylation of the NN-dimethylamide of a terminal acetylenic acid, or of an acetylenic alcohol, with final hydrolysis or oxidation, respectively. Eicosa-5,11,14-triynoic acid was prepared by alkylation of the Grignard complex of dodeca-5,11-diynoic acid with oct-2-ynyl bromide by Osbond's method. Catalytic semihydrogenation of these acetylenic acids has been examined.