反应详情

To a mixture of 3.21 g (19.9 mmol) of 2,4-dihydroxyquinoline and 1.87 g (27.1 mmol) of NaNO2 in 60 mL of 0.2N NaOH in an ice-bath was added dropwise 40 mL of aqueous 2N H2SO4. The mixture was stirred in an ice bath for 1 h after addition of H2SO4, filtered and dried to leave 3.41 g of orange solid which was crystallized by boiling with 150 mL of ethanol (95%) and filtered. The filtrate was cooled to and kept at room temperature for 5 h. The crystalline precipitate was filtered and dried to leave 1.88 g (50%) of 10a as a red solid, mp 206° C. (decomposed, lit 208° C., dec.). 1H NMR (CDCl3 +DMSO-d6), 6.65-6.78 (m, 2), 7.15 (m, 1), 7.556 (d, 0.30, J=8.1), 7.605 (d, 0.70, J=8.1), 10.887 (s, 0.3), 11.346 (s, 0.7). MS, 190 (100, M+), 173 (25), 146 (55). High resolution MS, Calcd for C9H6N2O3, 190.0375, found 190.0400.

1. filtrationfiltered
2. customdried