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.