Hydrazine → Benzopyrano[4,3,2-de]phthalazine

Participants

Reaction Steps

Prepared from the compound 11 (R═H) and 1.5 equivalent of hydrazine to give benzopyrano[4,3,2-de]phthalazine according to General Procedure C. To a solution of 0.3 g of benzopyrano[4,3,2-de]phthalazine in 7.5 mL of concentrate sulfuric acid is dropwise added 2.0 mL of fuming sulfuric acid at 0° C. The mixture is stirred for 3 hours at 0° C. and poured into 100 mL of ice-cold water. The precipitation is collected by filtration, washed with water to give of a white solid product, mp>300° C. (dec.). 1H-NMR (400 MHz, DMSO-d6); 12.7 (s, 1H), 8.35 (s, 1H), 7.92-7.90 (m, H), 7.76-7.71 (m, 2H), 7.38 (d, 1 H).

Provenance & Evidence