N-(3,4-dihydro-2H-naphthalen-1-ylidene)hydroxylamine → 1,3,4,5-Tetrahydro-2H-1-benzazepin-2-one

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Reaction Steps

A mixture of 1.0 g (6.2 mmole) of 1-tetralone oxime and 10 g polyphosphoric acid was heated at 105° for 1 hr. The warm mixture was poured into 100 mL water with stirring. The pH was carefully adjusted to 6-7 by addition of solid sodium bicarbonate and the mixture was extracted with 60 mL ethyl ether. The organic phase was washed with 10 mL saturated sodium chloride, dried (MgSO4) and concentrated under reduced pressure. The residue was recrystallized from ether/hexane to give 1,3,4,5-Tetrahydro-benzo[b]azepin-2-one, 0.682 g, m.p. 141-142°.

Provenance & Evidence