[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[CH:2]1.[C:10](OC)(=O)C(OC)=O.CC(C)([O-])C.[K+].Cl>CN(C=O)C.O.C(OCC)C>[CH3:10][N:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[CH:2]1
The indole product from Example 56 (100 mg, 0.36 mmol) and dimethyl oxalate (46 mg, 0.39 mmol) in DMF (3 mL) were treated with potassium t-butoxide (44 mg, 0.39 mmol). The reaction was heated at reflux for 30 min. Reaction was cooled to room temperature and diluted with water (25 mL). Following extractions (3×) with ethyl acetate, the organic layers were washed with water, brine, dried over sodium sulfate, filtered and concentrated. The dark residue was chromatographed (SiO2, 20% EtOAc/hexanes), and the resulting oil was treated with 1 M HCl (1 eq) in diethyl ether to provide the N-methyl indole product as a white solid (45 mg, 11%): mp 255-258° C.; 1H NMR (300 MHz, CD3OD) δ 7.43-7.25 (m, 3H), 7.12-7.00 (m, 2H), 6.99 (d, J=10.0 Hz, 1H), 6.70 (d, J=8.6 Hz, 1H), 6.50 (d, J=3.1 Hz, 1H), 4.80-4.67 (m, 2H), 3.89 (dd, J=5.6, 11.9 Hz, 1H), 3.81 (s, 3H), 3.65-3.55 (m, 1H), 3.30-3.29 (m, 1H), 3.14 (s, 3H); IR (KBr) 3424, 2944, 2479, 1590, 1449 cm−1; CI MS m/z=295 [C19H19FN2+H]+.
Loading…
