Derivatization of keto fatty acids: VI. Synthesis, oxidation and mass spectrometry of dithiolanes

Abstract

The synthesis of alkyl chain‐substituted dithiolanes, bisdithiolane and disulfolanes from oxo acids and their decomposition to original oxo acids are described. Reactions of ethanedithiol with 2 oxo esters, methyl 10‐oxoundecanoate and methyl 12‐oxooctadecanoate, give excellent yield of the corresponding dithiolanes, which are oxidized to the respective disulfolanes by m‐chloroperbenzoic acid (m‐CPBA). A similar reaction of ethanedithiol with methyl 9,10‐dioxooctadecanoate affords bisdithiolane. Retroreactions of the dithiolanes and bisdithiolanes under acidic conditions and of disulfolanes under alkaline conditions yield the parent oxo acids. The structures of the individual reaction products have been established from analytical and spectral data and confirmed by a study of their mass spectra.