Reaction Steps
To 4-(2,4-dichlorophenyl)-1,3,6,6-tetramethyl-7,8-dihydro-4H-pyrazolo[3,4-e][1,4]thiazepine (0.1 g, 0.28 mmol, Ex. D.4), dissolved in dry acetonitrile/DMF (4:1, 5 mL), was added 3,3,3-trifluoro-1,2-propenoxide (0.5 mL, 5.45 mmol) and ytterbium triflate (0.05 g, 0.4 mmol). The reaction mixture was stirred, for about 72 h, at about 50° C. After cooling to rt, 5% aqueous sodium bicarbonate (25 mL) and ethyl acetate (25 mL) were added. 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/methanol/acetic acid (8:2:0.1) followed by ethyl acetate/methanol/acetic acid (5:5:0.1)), to afford crude product which was purified by prep-HPLC (Table 2, Method c) to yield 3-[4-(2,4-dichlorophenyl)-1,3,6,6-tetramethyl-4,7-dihydropyrazolo[3,4-e][1,4]thiazepin-8-yl]-1,1,1-trifluoro-propan-2-ol (0.077 g, 0.16 mmol, 58%), as a white solid: LC-MS (Table 1, Method a) Rt=2.71 min, m/z 468 (M+H)+; 1H NMR (400 MHz, CDCl3, diastereomer mixture, ratio A:B=54:46) δ ppm 1.04 (3 H, s) 1.38 (3 H, s) 1.87 (3 H, s) 3.43 (1 H, dd, J=14.7, 6.1 Hz) 3.65-3.75 (1 H, m) 4.07 (3 H, s) 4.11-4.28 (2 H, m) 4.41-4.50 (1 H, m) 5.22 (1 H, s) 7.30 (1 H, dd, J=8.3, 2.2 Hz) 7.46 (1 H, d, J=2.2 Hz) 7.50 (1 H, d, J=8.3 Hz) 8.93 (1H, t, J=4.8 Hz) (Isomer A); 1H NMR (400 MHz, CDCl3) δ ppm 1.01 (3 H, s) 1.36 (3 H, s) 1.90 (3 H, s) 3.37 (1 H, dd, J=14.6, 7.1 Hz) 3.65-3.75 (1 H, m) 3.98 (3 H, s) 4.11-4.28 (2 H, m) 4.50-4.60 (1 H, m) 5.17 (1 H, s) 7.29 (1 H, dd, J=8.3, 2.2 Hz) 7.44 (1 H, d, J=2.2 Hz) 7559 (1 H, d, J=8.3 Hz) 8.83 (1 H, t, J=4.8 Hz) (Isomer B).
