Triethylamine → 7-Bromo-2-oxo-1,2,3,5-tetrahydro-pyrido[2,3-e][1,4]diazepine-4-carboxylic acid benzyl ester

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Reaction Steps

A suspension of 7-bromo-1,3,4,5-tetrahydro-pyrido[2,3-e][1,4]diazepin-2-one (1.08 g, 4.46 mmol) in CH2Cl2 (60 mL) was treated with Et3N (0.80 mL, 5.7 mmol) and then cooled in an ice bath. The chilled suspension was treated dropwise with CbzCl (4.5 mmol) to give a clear solution. The ice bath was removed and the solution was allowed to stir overnight. The mixture was diluted with CH2Cl2 (90 mL), washed with H2O (50 mL) and brine (50 mL), dried over Na2SO4, filtered and the solvent was removed in vacuo. Purification by flash column chromatography (silica gel, CH2Cl2/MeOH, 99.5:0.5 to 99:1) gave the title compound (0.52 g, 31%) as a white solid: 1H NMR (300 MHz, CDCl3) δ 8.31-8.36 (m, 2H), 7.49-7.71 (m, 1H), 7.34-7.40 (m, 4H), 7.19-7.21 (m, 1H), 5.08-5.12 (m, 2H), 4.43-4.65 (m, 4H); MS (ESI) m/e 376 (M+H)+.

Provenance & Evidence