1-Hydroxybenzotriazole → (+)-(3,5-Dimethylbenzoyl)-3-(3,4-dichlorophenyl)piperazine

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Reaction Steps

To a solution of BOC glycine (0.918 g, 5.24 mmol), (+)-(3,5-dimethylbenzoyl)-3-(3,4-dichlorophenyl)piperazine (enantiomer B)(1.80 g, 4.95 mmol) (prepared in Example 19), DEC (0.983 g, 5.13 mmol), HOBT (0.687 g, 5.07 mmol) and Hunig's base (0.92 mL, 5.1 mmol) in CH2Cl2 (100 mL) was left stirring for 2.5 d. The reaction mixture was added to CH2Cl2 (200 mL) and washed with sat. NaHCO3 (3×100 mL), brine (100 mL), dried with MgSO4 and concentrated. The crude material was treated with MeOH saturated HCl (25 mL) for 10 h and concentrated. The resulting residue suspended in 0.3N NaOH (150 mL) and extracted with CH2Cl2, (3×50 mL). The combinded organic layers were washed with brine (50 mL), dried with MgSO4, concentrated, and purified by flash chromatography on silica gel, eluting with 20:1:0.2 CH2Cl2 /MeOH/conc. aq. NH3 to give 0.95 g of the titled product as a white solid. HRMS (FAB, M+H+); m/e calc'd [C31H24Cl2N3O2 ]+ : 420.1246 found 420.1254.

Provenance & Evidence