A solution of 5-iodo 3-methoxy-4-n-propoxybenzaldehyde (26 g, 0.08 mol) in DMF (75 ml) was added over 15 minutes to a stirred solution of sodium cyanide (4 g, 0.08 mol) in DMF (100 ml) at 35° C. After stirring for 20 minutes, a solution of 3-dimethylamino-1-(3,4,5-trimethoxyphenyl)-1-propanone (18 g, 0.07 mol) in DMF (100 ml) was added over 0.5 hour. The mixture was stirred at 35° C. for 1 hour and kept at room temperature overnight. It was poured into ice-cold 20% hydrochloric acid (2 1), and the solid was filtered, dried by suction, and taken up in ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and the filtrate was evaporated to dryness. Crystallization from Et2O-hexane gave 1-(5-iodo-3-methoxy-4-n-propoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-1,4-butanedione, m.p. 120°-121° C.
