反応手順
Sodium borohydride (2.69 g, 71.3 nmol) was added to a stirred solution of the ester (49)(10.0 g, 33.6 mmol) in THF (50 mL) under an N2 atmosphere at room temperature. Effervescence was observed upon addition of the reducing agent. TLC (EtOAc) after 16 hours revealed the complete loss of starting material. The solution was concentrated and redissolved in EtOAc (100 mL). The organic layer was washed with sat. NH4Cl (5×100 mL) and concentrated in vacuo. Purification by flash chromatography (1% MeOH/CHCl3) yielded the product (50) as a yellow solid (6.46 g, 64%). MP=98-102° C. 1H NMR (250 MHz, CDCl3) δ 7.70 (s, 1H), 7.16 (s, 1H), 4.95 (d, J=6.5 Hz, 2H), 4.12 (t, J=6.2 Hz, 2H), 3.98 (s, 3H), 3.70 (s, 3H), 2.71 (t, J=6.5 Hz, 1H), 2.56 (t, J=7.1 Hz, 2H), 2.19 (pent, J=6.7 Hz, 2H). 13C NMR (67.8 MHz, CDCl3) 173.9 (C12), 154.6 (Cquat.), 147.3 (Cquat.), 139.6 (Cquat.), 133.2 (Cquat.), 111.0 (C6), 109.8 (C3), 68.6 (C9), 62.7 (C1), 56.7 (C8), 52.1 (C13), 30.7 (C11), 24.6 (C10). IR (cm−1) 3286, 2937, 2881, 1737, 1577, 1533, 1368, 1332, 1282, 1162, 1008, 979, 950, 872, 821, 755, 651. MS (M+) 299.0. Anal. Calcd for C13H17NO7: C, 52.17; H, 5.73; N, 4.68. Found: C, 52.41; H, 5.86; N, 4.67.
