Rare Sulfur-Containing Compounds, Kujounins A1 and A2 and Allium Sulfoxide A1, from Allium fistulosum ‘Kujou’

Three sulfur-containing compounds, kujounins A1 (1) and A2 (2) and allium sulfoxide A1 (3), were isolated from the acetone extract of Allium fistulosum ‘Kujou’. Their chemical structures were elucidated on the basis of physicochemical evidence, including X-ray crystallographic data. Compounds 1 and 2 possess three rings and an acetal structure and were obtained as complex compounds having disulfide and monosaccharide moieties. On the other hand, compound 3 has a thiolane skeleton derived from allicin. Naturally occurring compounds 1–3 have rare molecular skeletons. This study is the first to determine the absolute configuration of thiolane-type compounds.