benzyl ketone are reacted with 10 5 g 0 07 mole ethyl orthoformate in 10 ml of dimethyl formamide in the presence of 1 ml morpholine the reaction mixture is maintained at 80 u00b0 85 u00b0 c and in the second hour a solid precipitates after 6 hours 1oo ml of chloroform are added to the mixture the precipitated substance is filtered and dried 7 hydroxy 3 39 4 39 dimethoxy isoflavone is obtained ______________________________________analyses c sub 17 h sub 14 o sub 5 molecular weight 298calculated c 68 46 h 4 69 found c 68 30 h 4 72 ______________________________________ 47 4 g 0 15 mole 2 4 dihydroxy phenyl 3 4 ethoxy benzyl ketone are reacted with 31 5 0 21 mole ethyl orthoformate in 20 ml of dimethyl formamide in the presence of 3 ml morpholine the reaction mixture is maintained at 80 u00b0 85 u00b0 c for six hours upon cooling to 60 u00b0 c 100 ml of chloroform are added the precipitated substance is filtered and dried product 7 hydroxy 3 39 4 39 diethoxy isoflavone analysis for the formula c 19 h 18 o 5 a mixture of 75 kg dimethyl formamide 100 kg 420.