P-Anisidine → tert-butyl 6-[3-(4-methoxyanilino)-3-oxopropyl]-1,4,5,6-tetrahydroazepino[4,5-b]indole-3(2H)-carboxylate

Participants

Reaction Steps

3-(3-(tert-butoxycarbonyl)-2,3,4,5-tetrahydroazepino[4,5-b]indol-6(1H)-yl)propanoic acid (0.105 g, 0.292 mmol), p-anisidine (0.0377 g, 0.306 mmol, 1.05 equiv.) and dimethylaminopyridine (0.0357 g, 0.292 mmol, 1.00 equiv.) were dissolved in THF at rt under N2. Diisopropylcarbodiimide (0.0503 mL, 0.0405 g, 0.321 mmol, 1.00 equiv.) was added, then the reaction mixture was stirred for 29 h. The reaction mixture was taken up in EtOAc and washed with 10% aq. citric acid (2×), saturated aq. NaHCO3 (2×) and brine (1×). The organic layer was dried over MgSO4, filtered, and concentrated. The crude product (0.1686 g) was chromatographed (SiO2 25 g, eluted with 9:1 toluene: acetone) to give tert-butyl 6-[3-(4-methoxyanilino)-3-oxopropyl]-1,4,5,6-tetrahydroazepino[4,5-b]indole-3(2H)-carboxylate (0.113 g) in 84% yield. 1H NMR (300 MHz, CDCl3) δ 1.47, 2.68-2.76, 2.95-3.08, 3.56-3.70, 3.79, 4.53, 6.83, 7.12-7.54; MS (ESI+) for C27H33N3O4 m/z 464.0 (M+H)+.

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