Allium Chemistry: Synthesis of 1-[Alk(en)ylsulfinyl]propyl Alk(en)yl Disulfides (Cepaenes), Antithrombotic Flavorants from Homogenates of Onion (Allium cepa)

A series of 1-[alk(en)ylsulfinyl]propyl alk(en)yl disulfides (α-sulfinyl disulfides) of structure RS(O)CHEtSSR‘, R, R‘ = Me, (E,Z)-MeCHCH, n-Pr, and CH2CHCH2, termed cepaenes, have been synthesized by a variety of routes including oxidation of 1-[alk(en)ylthio]propyl alk(en)yl disulfides, RSCHEtSSR‘, termed deoxycepaenes. The cepaenes are identical to compounds isolated from homogenates of onion (Allium cepa) and to compounds identified in these homogenates by liquid chromatography/mass spectrometry, while the deoxycepaenes are identical to compounds found in Allium distilled oils and in other materials. The antithrombotic activities for several cepaenes are reported. Keywords: Allium chemistry; onion (Allium cepa); a-sulfinyl disulfides; cepaenes; antithrombotic compounds