Synthesis of terminally perfluorinated long-chain alkanethiols, sulfides and disulfides from the corresponding halides

Semifluorinated n-alkanethiols, symmetrical sulfides and disulfides bearing the chain(s) F(CF2)(n)(CH2)(m) with n=4, 6, 8, 10, and m=2, 11 have been p repared by various synthetic methods, starting from the corresponding iodid es or bromides. Methods based on sodium hydrogen sulfide, commonly used to accomplish this conversion, treatment of the Bunte salt obtained from sodiu m thiosulfate, the basic hydrolysis of isothiouronium salts, the hydrolysis under mild conditions of thiophosphorates formed from sodium thiophosphate and the basic hydrolysis of thiol acetic acid derivatives, have been inves tigated and compared relatively to the selective synthesis of the title com pounds. The thiolacetic route yields essentially the thiols with some amoun ts of disulfides. Results from thiourea appears similar. Sodium thiophospha te constitutes an excellent route for the synthesis of thioethers, particul arly when starting from the bromides. The two classical methods based on so dium hydrogen sulfide and sodium thiosulfate exhibit poor selectivity. It h as been possible to obtain all the sulfur compounds reported in the pure st ate. (C) 2000 Elsevier Science S.A. All rights reserved.