Synthesis of Estrogenic Isoflavone Derivatives

Natural estrogens in plants have assumed considerable importance since the demonstration of their presence in subterranean clover by Bennetts (1) in 1946 and the identification of the isoflavone, genistein (V, 4\u27, 5, 7-OH) as the probable substance responsible for some of the estrogenic activity by Curnow and Bennetts (2) in 1952. Earlier the isoflavones were found in soybean meal as genistein glucoside (3) (5), methyl genistein (V, 6\u27,5, 7,-OH,8- CH3), isogenistein (V,6\u27,5,7-OH), tatoin (V,4\u27,5-OH,8-CH3) ( 4), daidzein (V,4\u27,7-OH) and formononetin (V,4\u27-OCH3,7-OH) (5). Furthermore the isoflavone biochanin A (V, 4\u27-OCH3, 5, 7-OH) was isolated from chana seed by Bose and Siddique (6) and formononetin from subterranean clover by Bradbury and White (7)