A mixture of ethyl vinyl sulphone (600 mg), 5-bromo-3-(1-methyl-4-piperidinyl)-1H-indole (1.00 g), palladium acetate (50 mg), tri-o-tolylphosphine (244 mg) and triethylamine (700 mg) in dry dimethylformamide (10 ml) was stirred and heated at 100°-110° for 4 h. The dimethylformamide and triethylamine were removed in vacuo. The residual gum was chromatographed on silica (140 g; Merck 9385), using a mixture of dichloromethane, ethanol and ammonia (80:8:1) as the eluant, to give a gum (750 mg). The material was rechromatographed on silica (Merck 9385; 100 g), using a mixture of dichloromethane, ethanol and ammonia (90:8:1) as the eluant. Fractions containing mainly the product were combined and evaporated to give a gum. A few fractions contained small amounts of the pure product. These were kept separate, combined and evaporated. The residual gum was crystallised from a small amount of a mixture of ethyl acetate and cyclohexane. Some of the crystals were then used to seed the crystallisation of the main batch of the product, also from a mixture of ethyl acetate and cyclohexane. The two batches of solid product were combined and dried in vacuo to give the title compound (310 mg) as a powder, with m.p. 98°-102°.
