3-Methyl-1-(2-naphthylsulphonyl)piperazine (1.8 g) and triethylamine (3.18 ml) were added in turn to a stirred solution of 1-(4-pyridyl)piperidine-4-carbonyl chloride (1.54 g) in methylene chloride (20 ml) and the mixture was stirred at ambient temperature for 16 hours. The mixture was partitioned between ethyl acetate and water. The organic phase was washed with water, dried (MgSO4) and evaporated. The residue was purified by column chromatography using a 89:10:1 mixture of ethyl acetate; methanol and ammonia as eluent. The material so obtained was triturated under diethyl ether to give 3-methyl-1-(2-naphthylsulphonyl)-4-[1-(4-pyridyl)piperidin-4-yl-carbonyl]piperazine (32% yield);
