反应详情

The crude Nα -(9-fluorenylmethoxycarbonyl)-O-(9-phenyl-9H-fluoren-9-yl)-L-serine methyl ester from Step 1 (Method A) was dissolved in piperidine (5 mL) and the mixture stirred at 60 (C for 0.5 h. After evaporation of the solvent the residue was chromatographed on silica gel with ethyl acetate to give 6.96 g (yield 97%) O-(9-phenyl-9H-fluoren-9-yl)-L-serine methyl ester as a viscous oil. 1H NMR (CDCl3, 300 MHz) δ: 7.65 (d, 2H), 7.40-7.05 (m, 11H), 3.65 (s, 3H), 3.46 (t, 1H), 3.30-3.10 (m, 2H), 1.80 (br s, 2H); 13C NMR (CDCl3, 75 MHz) δ: 174.1, 146.4, 146.2, 142.7, 140.4, 129.0, 128.9, 128.1, 127.9, 126.9, 125.2, 125.1, 124.9, 119.8, 119.7, 88.1, 65.1, 54.6, 51.8, 51.7, 13.9.

1. customAfter evaporation of the solvent the residue
2. customwas chromatographed on silica gel with ethyl acetate