Triethylamine → 2,3,5,6-Tetrafluorophenyl 3-(tert-butyloxycarbonyl)-1,2-dihydro-3H-pyrrolo[3,2-e]indole-7-carboxylate

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Reaction Steps

2,3,5,6-Tetrafluorophenyl trifluoroacetate (2.6 g, 10 mmol) was added dropwise to a solution of 3-(tert-butyloxycarbonyl)-1,2-dihydro-3H-pyrrolo[3,2-e]indole-7-carboxylic acid (1.0 g, 3.7 mmol, D. L. Boger, R. S. Coleman, and B. J. Invergo. J.Org.Chem., 1987, Vol.52, 1521-1530) and triethylamine (1.5 ml, 10 mmol) in 10 ml of anhydrous CH2Cl2. After 4 hrs, CH2Cl2 was removed by evaporation at reduced pressure. Flash chromatography (4×20 cm, hexane-ethyl acetate, 1:2) afforded 1b as a yellow crystalline solid (1.25 g, 75%): 1H NMR (Me2SO-d6, 200 MHz, ppm) 12.39 (d, 1H, J=1.4 Hz, NH), 8.02 (m, 1H, C6F4H), 7.9 (br s, 1H, C4-H), 7.45 (d, 1H, J=1.4 Hz, C8-H), 7.33 (d, 1H, J=9 Hz, C5-H), 4.02 (t, 2H, J=9 Hz, NCH2CH2), 3.26 (t, 2H, J=9 Hz, NCH2CH2), 1.51 (s, 9H, C(CH3)3). Anal. Calcd. for C22H18N2O4F4 : C, 58.67; H, 4.03; N, 6.22. Found: C, 58.45; H, 4.09; N, 6.13.

Provenance & Evidence