Potassium Hydroxide → 2,3,4,5-Tetrahydro-1,5-benzoxazepine

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Reaction Steps

Powdered KOH (37.60 g, 0.67 mol) was added to a slurry of 3-(3-chloropropyl)-1,3-benzoxazol-2(3H)-one (35.75 g, 0.169 mol) in n-butanol (450 mL) under N2 gas and refluxed for 52 hours. The mixture was filtered and reduced to dryness under reduced pressure. The residue was taken up in H2O (500 mL) and extracted with ether (3×200 mL). The organic was washed with 10% HCl (2×200 mL), dried over MgSO4, and stripped of solvent under reduced pressure. Purification by flash chromatography (50% EtOAc in hexanes) yielded 13.72 g (54%) of 2,3,4,5-tetrahydro-1,5-benzoxazepine as a powder, m.p. 50-51° C. (M+H)+ 149.

Provenance & Evidence