0.4 ml of ethyl thiocyanate and 0.45 ml of stannic chloride were added to a solution of 1 g of methyl 4-(3-oxo-2-phenyl-heptyl) benzoate of Step C in 20 ml of phosphorous oxychloride and the mixture was stirred for 10 hours at reflux, then poured into ice-cooled water. The mixture was stirred for 15 minutes and alkalized with concentrated ammonium hydroxide. Extraction was carried out with ethyl acetate and the extracts were washed with water, dried and evaporated to dryness. The residue was chromatographed on silica (eluant: hexane - ethyl acetate (9-1)) to obtain 0.57 g of the desired product melting at 70° C.
