Ethyl bromoacetate → 3-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde

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Reaction Steps

(6-Bromo-2-nitro-pyridin-3-yloxy)-acetic acid ethyl ester. To a suspension of 6-bromo-2-nitro-pyridin-3-ol (3.07 g, 14.0 mmol) in acetone (20 mL) was added K2CO3 (3.93 g, 28.0 mmol) and ethyl bromoacetate (1.55 mL, 14.0 mmol). The mixture was heated to reflux and stirred for 20 h. The resulting suspension was cooled to RT, diluted with Et2O (100 mL) and filtered. The filtrate was concentrated to afford 3.14 g (74%) of the title compound, which was used without further purification. MS (ESI): exact mass calculated for C9H9BrN2O5, 303.97; m/z found, 305.2 [M+H]+. 1H NMR (400 MHz, CDCl3): 7.67 (d, J=8.6, 1H), 7.35 (d, J=8.7, 1H), 4.78 (s, 2H), 4.27 (q, J=7.1, 2H), 1.30 (t, J=8.5, 3H).

Provenance & Evidence