反应详情

A mixture of the crude compound of step 8, LiOH (3.0 equiv.) and 50 ml of 5:1 THF/water was stirred at room temperature for 15 minutes. The reaction mixture was slightly acidified to pH <7 by adding 2N HCl and then evaporated to dryness under vacuum. The residue was dissolved in a chloroform and methanol mixture, adsorbed on silica (100-200 mesh) and purified by flash chromatography on silica gel, and then eluted with 2-15% methanol in chloroform to provide the title compound as a pale green solid after drying in vacuo; 1H NMR (300 MHz, DMSO-d6) δ: 0.85-0.88 (d, J=6.6 Hz, 6H), 2.14-2.19 (m, 1H), 2.34 (s, 3H), 3.92-3.96 (m, 1H), 7.11-7.16 (m, 2H), 7.24-7.31 (m, 1H), 7.60 (S, 1H), 7.67-7.70 (d, J=8.7 Hz, 1H), 7.76 (s, 1H), 8.01-8.04 (m, 2H), 8.86 (s, 1H), 9.24 (s, 1H); ms (ESI) m/z 473.2 [M+H]+.

1. customevaporated to dryness under vacuum
2. dissolutionThe residue was dissolved in a chloroform and methanol mixture
3. custompurified by flash chromatography on silica gel
4. washeluted with 2-15% methanol in chloroform