Sulfuric Acid → 2,3,4,5-tetrahydro-1H-1-benzazepine-2,5-dione

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Reaction Steps

To 10 mL of H2SO4 (97% ) cooled in an ice-bath was added portionwise 1.08 g (6.86 mmol) of 1,4-naphthoquinone and it was stirred to become a solution. To the red solution was added portionwise 0.454 g (6.98 mmol) of NaN3. The mixture was stirred in ice bath for 2 h, then at room temperature for 2 days. It was added dropwise into 100 mL of ice-water and stirred for 1 h and allowed to stand overnight. The mixture was filtered and washed thoroughly by water, dried to leave brown solid 1.02 g. 1H NMR (CDCl3 +DMSO-d6) shows it is more than 80% pure. Portion of the solid was crystallized (DMSO/H2O) to give 32 as a brown solid, mp 225°-226° C. 1H NMR (CDCl3 +DMSO-d6) 6.544 (d, 1, J=12.9), 6.657 (d, 1, J=12.9), 6.978 (t, 1, J=7.5), 7.152 (d, 1, J=8.4), 7.323 (t, 1, J=7.5), 7.812 (d, 1, J=8.1), 10.55 (bs, 1).

Provenance & Evidence