Cyclic sulfur-containing compounds from Allium fistulosum ‘Kujou’

Sulfur-containing compounds, allicin and ajoene, etc., were isolated from Allium species. In a recent study, some sulfur-containing cyclic compounds were isolated from A. sativum , A. cepa , and A. fistulosum . Four new compounds with multiple rings with methyl disulfide or propyl disulfide at the side chain of the 7-position, kujounins A 3 ( 1 ), B 1 ( 2 ), B 2 ( 3 ) and B 3 ( 4 ), and two new thiolane type compounds with methoxy and methyl sulfoxide moiety at the 2- and 5-positions, and allium sulfoxides A 2 ( 5 ) and A 3 ( 6 ), were isolated from the acetone extract of the fresh white parts of Allium fistulosum ‘Kujou’ with three known compounds, kujounin A 1 ( 7 ) and A 2 ( 8 ), and allium sulfoxide A 1 ( 9 ). The chemical structures of the new compounds were elucidated on the basis of physicochemical evidence. The kujounins had a rare molecular skeleton, which was tetrahydro-2 H -difuro[3,2- b :2′,3′- c ]furan-5(5a H )-one.