With potassium carbonate In water pH=10
Experimental Procedure The salt (-)-32HBr was basified topH 10 with 0.1Maq. K2CO3 and extracted with DCM (5 5 mL). Thecombined organic layers were washed with brine (25 mL), driedover MgSO4, filtered, and concentrated in vacuo (without heating) to afford (-)-3 (14 mg, 93percent) as a white solid. Mp 143e145 C;{lit.,9 Mp 160 C (decomp.)}; [a]D20 5.4 (c 0.50, EtOH); {lit.,9[a]D2010 (c 0.5, DMF)}; IR (neat): 3128, 2926, 2852, 1722, 1674,1607, 1448, 1382, 1309, 1223, 1106, 1075, 1043, 900 cm1; HRMS(ESI): calcd. for [C16H1779Br35ClN3O3 H] 414.0220, found 414.0212;1H NMR ((CD3)2SO, 500 MHz): d 1.16e1.42 (m, 2H), 1.52e1.61 (m,1H), 1.84e1.95 (m, 1H), 2.32e2.40 (m, 1H), 2.45 (dd, J 15.5, 9.0 Hz,1H), 2.64 (td, J 9.0, 4.0 Hz, 1H), 2.75e2.84 (m, 1H), 2.93e3.03 (m,2H), 4.76 (d, J 6.0 Hz, 1H), 4.94e5.06 (m, 2H), 8.16 (s, 1H), 8.22 (s,1H), 8.24 (s, 1H) ppm (OH not visible by 1H NMR spectroscopy); 13CNMR ((CD3)2SO, 125 MHz): d 26.3 (CH2), 34.7 (CH2), 44.1 (CH2), 46.0(CH2), 55.3 (CH2), 60.5 (CH), 71.2 (CH), 122.2 (C), 127.4 (CH), 128.8(C), 132.2 (C), 132.8 (CH), 147.8 (C), 150.2 (CH), 159.1 (C), 203.9 (C)ppm. | 93% |