A solution of 2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyridine (409 mg) and triethylamine (202 mg) in dry dichloromethane (20 ml) was stirred under nitrogen and cooled in an ice-bath while a solution of 2-chloro-5-pyridinesulphonyl chloride (212 mg) in dry dichloromethane (10 ml) was added dropwise. The reaction mixture was allowed to warm to room temperature and stirring continued for a further 3 hours. The solvent was evaporated and the residue chromatographed on silica, eluting with dichloromethane. Appropriate fractions were combined and evaporated and the residue recrystallised from ethyl acetate to give the title compound (320 mg), m.p. 140°-140.5° C. Found: C, 51,27; H, 4.63; N, 7.25. C25H27Cl2N3O7 requires C, 51.37; H, 4.66; N, 7.19%.
