Sodium Hydroxide → 1,2,3,4-Tetrahydro-benzo(b)azepin-5-one

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Reaction Steps

To preheated polyphosphoric acid (PPA, 220 g) at 70-80° C. was added 1-(Toluene-4-sulfonyl)-1,2,3,4-tetrahydro-benzo[b]azepin-5-one (50.0 g, 0.16 mol). The mixture was stirred for 3.0 h at the same temperature and then poured into ice water. After the pH was adjusted to about 8-9 by adding aq NaOH, the mixture was extracted with ethyl acetate. The organic layer was separated, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography (eluent, 3:1 n-hexanes:ethyl acetate) to give 1,2,3,4-Tetrahydro-benzo[b]azepin-5-one (22 g).

Provenance & Evidence