Yield:98589-40-3 94%

Reaction Conditions:

with hydrogen;5% palladium over charcoal in methanol;ethyl acetate; for 2 h;

Steps:

1.13a

To a solution of 6-nitrochromone (2.0 g, 10.5 mmol) in methanol/ethyl acetate (100 mL/20 mL) purged with argon, was added 5% Pd/C (Degussa-wet, 0.5 g) catalyst. Hydrogen gas was bubbled through the slurry with stirnng until (2 hrs.) LCMS and TLC showed complete conversion of starting material to product. The spent palladium catalyst was filtered off through a celite, and the solid was washed with methanol. The combined filtrate and washings were evaporated to produce 6-amino-chromen-4-one (1.58 g, 94%) as a light yellow solid. LCMS m/z (%)=162 (M+H, 100), 1H NMR (400 MHz, CDCl₃) δ: 7.79 (d, J=5.96 Hz, 1H), 7.38 (d, J=2.86 Hz, 1H), 7.29 (d, J=8.88 Hz, 1H), 7.01 (dd, J=8.80 Hz, 2.8 Hz, 1H), 6.26 (d, J=5.96 Hz, 1H), 5.29 (s, 2H).

References:

US2007/207994,2007,A1 Location in patent:Page/Page column 56