Reaction Steps
3 N HCl (7 mL) was added to the solution of 4-{(R)-((2R,5 S)-4-allyl-2,5-dimethylpiperazin-1-yl) [3-(tert-butyl-dimethylsilanyloxy)-phenyl]methyl}-N,N-dimethylbenzenesulfonamide (1.3 g) in tetrahydrofuran (15 mL). The mixture was stirred at room temperature overnight. Water (15 mL) was added to the reaction. The reaction mixture was extracted with diethyl ether (25 mL×3). The remaining water layer was neutralized by 10% aqueous NaOH to pH=8-9 and then extracted with ethyl acetate (30 mL×3). The combined ethyl acetate layers were washed with water (20 mL×3) and brine (20 mL), dried over sodium sulfate and concentrated to give 0.83 g of crude product. The crude product was purified by silica gel chromatography conducted on CombiFlash™ Sq 16× (gradient: 100% CH2Cl2 to 7% MeOH in CH2Cl2) to give 4-[(R)-((2R,5S)-4-allyl-2,5-dimethylpiperazin-1-yl)(3-hydroxyphenyl)methyl]-N,N-dimethylbenzenesulfonamide (720 mg; 70%). 1H NMR (300 MHz, CDCl3) δ 7.71 (d, 2H, J=8.5 Hz), 7.35 (d, 2H, J=8.5 Hz), 7.14 (dd, 1H, J=8.0, 8.0 Hz), 6.89 (bs, 1H), 6.85 (d, 1H, J=8.0 Hz), 6.68 (d, 1H, J=8.0, 2.5 Hz), 5.83 (1H, m), 5.24-5.12 (m, 3H), 3.32 (dd, 1H, J=13.5, 5.0 Hz), 2.86 (dd, 1H, J=13.5, 8.0 Hz), 2.78 (dd, 1H, J=11.5, 3.0 Hz), 2.72 (s, 6H), 2.65 (dd, 1H, J=11.0, 2.5 Hz), 2.51 (m, 2H), 2.14 (dd, 1H, J=11.5, 9.0 Hz), 1.81 (dd, 1H, J=11.0, 9.5 Hz), 1.16 (d, 3H, J=6.0 Hz), 0.98 (d, 3H, J=6.0 Hz); MS (FAB, glycerol) m/z: 444 (M++H), 290, 153; Found: C, 58.32; H, 6.66; N, 8.18. Calc. (C24H33N3O3S 0.8 CH2Cl2):C, 58.23; H, 6.82; N, 8.21.
