Ethyl alpha-oxobenzenebutanoate → 3-[N-(1-carboethoxy-3-phenylpropyl)amino]-2,3-dihydro-1,5-benzoxazepin-4(5H)-one

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Reaction Steps

The 3-amino-2,3-dihydro-1,5-benzoxazepin-4(5H)-one (0.250 g) is dissolved in 5 ml of methanol and 2.88 g of ethyl 2-oxo-4-phenylbutyrate is added. This is followed by the addition of a solution of 88 mg of sodium cyanoborohydride in 3 ml of methanol and 0.8 ml of glacial acetic acid. The reaction is stirred overnight under nitrogen and concentrated. The residue is dissolved in 20 ml of methylene chloride and washed with 10 ml of cold saturated sodium carbonate. After drying over magnesium sulfate the solution is concentrated to an oil which is purified by flash chromatography on silica gel [solvent, acetone, hexane (1:4)] to afford 3-[N-(1-carboethoxy-3-phenylpropyl)amino]-2,3-dihydro-1,5-benzoxazepin-4(5H)-one; NMR (CDCl3) δ 9.35 (s (broad, 1], 6.50-7.30 (m, 10, 4.10 (q, 2), 2.67 (t (broad), 2], 1.21 (t, 3); IR (neat) 3220 (NH), 1730 (C=O, ester), 1685 (C=O, lactam) cm-1.

Provenance & Evidence