Irisones A and B: Two New Isoflavones from Iris missouriensis

Abstract

Two new isoflavones, irisones A and B, together with the known compound, 5,7-dihydroxy-2',6-dimethoxy isoflavone, were isolated from the roots of Iris missouriensis. With the help of 2D-homonuclear-J-correlation and 2D-nOe experiments the structure of irisone A was deduced to be 5-hydroxy-2'-methoxy-6,7-methylenedioxy isoflavone. The structure of irisone B was elucidated by spectral analyses as 2',5-dihydroxy-6,7-methylenedioxy isoflavone and was confirmed by chemical conversion to irisone A.