Potassium Carbonate → HCID 67317716, compound

Participants

Reaction Steps

To a solution of 3-(2-acetoxymethyl-4-benzyloxy-phenyl)-2-tert-butoxycarbonylamino-propionic acid methyl ester (1.85 g, 4.0 mmol) in methanol (40 mL) was added potassium carbonate (560 mg, 4.0 mmol) at room temperature and stirred for 1 h. The reaction mixture was diluted with dichloromethane (150 mL), washed with 1.0 M aqueous hydrogen chloride and dried (Na2SO4) to give the pure 3-(4-benzyloxy-2-hydroxymethyl-phenyl)-2-tert-butoxycarbonylamino-propionic acid methyl ester in almost quantitative yield. To the alcohol (800 mg, 1.93 mmol) in dichloromethane (50 mL) was added methanesulfonyl chloride (0.18 mL, 2.3 mmol) followed by triethylamine (0.38 mL, 2.70 mmol) at 0° C. and then brought to room temperature. After 1 h, the reaction mixture was washed with aqueous sodium hydrogencarbonate, dried (Na2SO4). The solvent was removed, dissolved the crude product in anhydrous THF (20 mL) followed by addition of 2.0 M solution of methylamine in THF (10 mL) in a sealed tube. The sealed tube was heated at 80° C. for a period of 12 h and then removed the solvent. The crude product was purified by flash chromatography using 30% ethyl acetate in hexane to give (8-benzyloxy-2-methyl-3-oxo-2,3,4,5-tetrahydro-1H-benzo[c]azepin-4-yl)-carbamic acid tert-butyl ester in 39% overall yield. 1H NMR (500 MHz, CDCl3): in δ 7.40-7.31 (m, 5 H), 7.01-7.00 (m, 1 H), 6.83-6.82 (m, 1 H), 6.66 (s, 1 H), 5.91-5.90 (m, 1 H), 5.13-5.01 (m, 4 H), 3.50-3.46 (m, 1 H), 3.03 (s, 3 H), 2.85-2.78 (m, 1 H), 1.45 (s, 9 H).

Provenance & Evidence