Methyl iodide → 1-Methyl-6-nitroindoline

Participants

Reaction Conditions

Reaction Steps

1-Methyl-2,3-dihydro-1H-indol-6-ylamine. 6-Nitroindoline (2 mmol) was combined with methyl iodide (2.2 mmol), n-Bu4I (7.4 mg, 0.020 mmol), and K2CO3 (350 mg, 2.5 mmol) in acetone (10 mL). The mixture was stirred at 25° C. for 16 h. The mixture was partitioned between CH2Cl2 and satd. aq. NaHCO3 (20 mL), and the organic layer was dried and concentrated. Purification by silica gel chromatography provided 1-methyl-6-nitroindoline (300 mg, 84%). To a solution of 1-methyl-6-nitroindoline (194 mg, 1.15 mmol) in MeOH (2 mL) was added FeCl3.6H2O (3 mg), Me2NNH2 (0.80 mL, 11 mmol), and charcoal (25 mg). The mixture was heated at reflux for 4 h. The mixture was filtered through diatomaceous earth, and the filtrate was concentrated to provide the desired compound in quantitative yield. Step B. (1-Benzyl-piperidin-4-yl)-(1-methyl-2,3-dihydro-1H-indol-6-yl)-amine. The product from Step A (161 mg, 1.1 mmol) was converted to the desired compound as in Example 2, Step B. Step C. The title compound (80 mg, 35%) was prepared as in Example 2, Step C. 1H NMR (500 MHz, CDCl3): 7.63 (d, J=15.5 Hz, 1H), 7.30-7.25 (m, 10H), 7.02 (d, J=7.4 Hz, 1H), 6.38-6.36 (d, J=8.8 Hz, 1H), 6.25 (d, J=15.5 Hz, 1H), 6.14 (s, 1H), 4.73-4.68 (m, 1H), 3.46-3.34 (m, 4H), 3.02-2.86 (m, 4H), 2.73 (s, 3H), 2.17-2.12 (m, 2H), 1.86-1.77 (m, 2H), 1.61-1.51 (m, 2H). MS: exact mass calculated for C30H33N3O, 451.26; m/z found, 452.2 [M+H]+.

Provenance & Evidence