Nitrogen → 2H-3-Benzazepin-2-one, 1,3,4,5-tetrahydro-

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Reaction Steps

beta-Tetralone (34 mmol) was suspended in 300 mL of 85% H3PO4 and treated portion wise with NaN3 (68 mmol) with vigorous stirring over a period of 1 h. During this time the reaction mixture was brought slowly to about 70° C. After stirring for a further 2 h at 70° C., no more N2 evolution was observed. The reaction mixture was cooled to RT, then poured into cold H2O (400 mL) and extracted with CHCl3 (3×). The organic layer was dried (MgSO4), concentrated and the residue was dissolved in EtOAc and the solid was filtered and washed with EtOAc to yield 4,5-dihydro-1H-benzo[d]azepin-2(3H)-one as a white solid (20% yield) along with a varying amount of the other region isomer 1,2,4,5-tetrahydrobenzo[c]azepin-3-one.

Provenance & Evidence