Triethylamine → (3R,4R)-4-(4-Bromo-2-nitro-phenylamino)-3-hydroxy-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Heat a mixture of (3R,4R)-4-amino-3-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (0.02 mol, 6.0 g), 5-bromo-2-fluoronitrobenzene (0.03 mol, 6.71 g) and triethyl amine (0.058 mol, 5.88 mL) in ethyl acetate (180 mL) to reflux for 16 h. Cool the reaction mixture to room temperature, dilute with ethyl acetate, and wash with water and brine. Dry the organic layer over anhydrous sodium sulfate, filter, and concentrate to obtain the title compound (12.35 g, crude). 1H NMR (400 MHz, CDCl3) δ 1.46 (s, 9H), 1.50-1.51 (m, 1H), 2.08-2.12 (m, 1H), 2.93 (dd, 1H), 3.01 (br s, 1H), 3.55-3.61 (m, 1H), 3.62-3.68 (m, 1H), 3.68 (br s, 1H), 4.13-4.18 (m, 1H), 6.97 (d, 1H), 7.48 (dd, 1H), 8.08 (d, 1H), 8.30 (d, 1H). ES-MS m/z 316 [M−Boc]+.

Provenance & Evidence