Dimethyl Sulfate → HCID 76287351, compound

Participants

Reaction Steps

To 4-(2,4-dichlorophenyl)-1,3,6,6-tetramethyl-4,8-dihydropyrazolo[3,4-e][1,4]thiazepin-7-one (0.150 g, 0.4 mmol, made in the same manner as Preparation C.2) dissolved in THF/H2O (1:1, 10 mL), was added NaOH (0.81 mL, 2 M aqueous). The reaction mixture was stirred for about 24 h at rt. Subsequently, dimethylsulfate (0.077 mL, 0.8 mmol) was added, and the reaction mixture was stirred for about 1 hr at rt. To the reaction mixture was added NH4OH (1 mL, 25% aqueous), followed by 5% aqueous sodium bicarbonate (5 mL) and ethyl acetate (25 mL). The layers were separated and the organic layer was washed with water (25 mL), dried (MgSO4), filtered and concentrated in vacuo. The resulting residue was purified by column chromatography (SiO2, ethyl acetate/DCM (1:9)), to afford 4-(2,4-dichlorophenyl)-1,3,6,6,8-pentamethyl-4H-pyrazolo[3,4-e][1,4]thiazepin-7-one (0.110 g, 0.28 mmol, 72%), as a white solid. LC-MS (Table 1, Method a) Rt=5.05 min, m/z 384 (M+H)+; 1H NMR (400 MHz, CDCl3) δ ppm 1.05 (3 H, br. s.) 1.51 (3 H, br. s.) 2.32 (3 H, br. s.) 2.87 (3 H, br. s.) 3.65 (3 H, br. s.) 5.32 (1 H, br. s.) 7.29 (1 H, dd, J=8.3, 1.9 Hz) 7.34 (1 H, br. s.) 7.72 (1 H, d, J=8.3 Hz).

Provenance & Evidence