3-Chlorobenzoic Acid → 5-[2-Ethoxy-5-(4-ethyl-4-oxidopiperazin-1-ylsulphonyl)pyridin-3-yl]-3-ethyl-2-(pyridin-2-yl)methyl-2,6-dihydro-7h-pyrazolo[4,3-d]pyrimidin-7-one

Participants

Reaction Steps

A mixture of the title compound of Example 1 (180 mg, 0.32 mmol), 3-chlorobenzoic acid (13 mg, 0.08 mmol) and dichloromethane (10 ml) was stirred at room temperature for 20 minutes, 3-chloroperoxybenzoic acid (112 mg, 0.32 mmol) added and the reaction mixture stirred for a further 18 hours, then partitioned between dichloromethane (20 ml) and aqueous sodium bicarbonate solution (10 ml). The phases were separated, the aqueous phase extracted with dichloromethane (2×20 ml) and the combined organic solutions dried (MgSO4) and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, using dichloromethane:methanol (80:20) as eluant, to furnish the title compound (82 mg, 45%) as a white powder. Found: C, 52.73; H, 5.67; N, 17.69. C26H32N8O5S; 0.50 CH2Cl2 requires C, 52.08; H, 5.44; N, 18.34%. δ (CDCl3): 1.30 (3H, t), 1.40 (3H,t), 1.58 (3H, t), 3.02 (2H, q), 3.20 (2H, m), 3.32 (4H, m), 3.48 (2H, m), 3.72 (2H, m), 4.76 (2H, q), 5.68 (2H, s), 7.08 (1H, d), 7.22 (1H, m), 7.63 (1H, m), 8.58 (1H, d), 8.65 (1H, s), 9.03 (1H, s), 10.70 (1H, s).

Provenance & Evidence