Synthesis of tetrathiafulvalene (TTF) derivatives substituted with two and four hydrophobic alkyl chains

Abstract

The synthesis of new tetrathiafulvalene (TTF) derivatives bearing two and four hydrophobic alkyl chains of varying lengths is described. 4,4′(5′)-Di-n-hexyl-TTF (10a) and 4,4′(5′)-di-n-octadecyl-TTF (10b) have been obtained, each as a mixture of two geometrical isomers, by elaboration of 1-bromooctan-2-one and 1-bromoeicosan-2-one, respectively. The bromoketones were converted in two steps into 4-alkyl-1,3-dithiole-2-thione intermediates and thence into 4-alkyl-1,3-dithiolium cation salts, which on treatment with triethylamine yielded the disubstituted TTF derivatives 10a and 10b. A modified route, starting from 6-chlorododeca-7-one yielded 2-diethylamino-4,5-dipentyl-1,3-dithiolium perchlorate salt which was converted, in two steps, into the 4,5-dipentyl-1,3-dithiolium cation and hence into tetrakis(n-pentyl)-TFF (3). © 1989.