Diisopropylethylamine → HCID 67403053, compound

Participants

Reaction Steps

N,N-Diisopropylethylamine (0.41 mL, 2.30 mmol) was added to a mixture of O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (321 mg, 0.84 mmol) and 4-{[(1,1-dimethylethyl)oxy]carbonyl}-2-nitrobenzoic acid (prepared according to Gao, Y. et. al WO2001070737) (205 mg, 0.77 mmol) in N,N-dimethylformamide (2 mL), and the reaction mixture was stirred at room temperature for 30 minutes. Ammonia was bubbled into the reaction mixture and stirring was continued for 45 minutes. The reaction mixture was quenched with 0.5M aqueous hydrochloric acid solution (20 mL) and extracted with ethyl acetate (3×20 mL), and the combined extract was washed with water (20 mL), then brine (20 mL), dried over sodium sulfate, filtered and concentrated. The residue was purified by silica gel flash chromatography (25 to 75% ethyl acetate in hexanes) to give the 1,1-dimethylethyl 4-(aminocarbonyl)-3-nitrobenzoate (160 mg, 78% yield). 1H NMR (400 MHz, CDCl3): 8.55 (s, 1H), 8.25 (d, 1H), 7.64 (d, 1H), 6.51 (br, 1H), 6.26 (br, 1H), 1.61 (s 9H); MS (EI) for C12H14N2O5: 267 (MH+).

Provenance & Evidence