Abstract
Lenthionine, a highly sulfur-containing odorous substance, has been isolated from Lentinus edodes (Berk.) Sing [Shiitake Mushroom]. The compound represents the characteristic odor of the mushroom and the structure was established to be 1,2,3,5,6-pentathiepane (1) by physico-chemical measurements. 1,2,4,6-Tetrathiepane (II) and 1,2,3,4,5,6-hexathiepane (III) were also separated from the mushroom in minor quantities. All these cyclic methylene polysulfides from natural source were synthesized from simple starting materials. A precursor of lenthionine was isolated in a crystalline form. The compound was not stable and gradually decomposed into lenthionine and its analogs after being left standing at room temperature. The structure of this precursor (IV) is proposed on the basis of the conventional and high resolution mass spectral studies. Finally, the mechanisms of formation of lenthionine and its analogs from the precursor is discussed.
