AN EFFICIENT PREPARATION OF ACETYL ISOFLAVONE GLUCOSIDE

Minor components of isoflavones in soybeans, ranosyl)-3-(4-hydroxyphen yl)-4H-1-benzopyran-4-one (6 ''-O-acetyldaidzin, 5) and -hydroxy-3-(4- hydroxyphenyl)-4H-1-benzopyran-4-one (6 ''-O-acetylgenistin, 6), were efficiently prepared from 6 ''-O-malonyldaidzin (3) or 6 ''-O-malonylg enistin (4) by decarboxylation in N,N-dimethylformamide at 60 degrees C in 46% or 57% yield, respectively, This reaction may explain the inc rease in the amount of the acetate during toasting of soybeans.