Water → 4-(3-methoxy-propyl)-2,2-dimethyl-6-nitro-4H-benzo[1,4]oxazin-3-one

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Reaction Conditions

Reaction Steps

At 0° C., a solution of 2,2-dimethyl-6-nitro-4H-benzo[1,4]oxazin-3-one (35.8 g, 0.161 mol) and 1-methoxy-3-(p-toluenesulfonyloxy)propane (47.6 g, 0.195 mol) in DMF (720 ml) is treated with Kl (5.49 g, 33.1 mmol). After adding 60% of NaH (7.80 g, 0.195 mol) over 10 min, the mixture is stirred at 0° C. for 30 min, warmed to 60° C., stirred for 14 h, and treated with H2O (3500 ml). After the extraction of the mixture with EtOAc (3×400 ml) and Et2O (3×400 ml), the combined org. layer is washed with H2O (2×250 ml), dried (Na2SO4), and evaporated. A SiO2 flash chromatography (2000 g, hexane/EtOAc 5:2) gives 4-(3-methoxy-propyl)-2,2-dimethyl-6-nitro-4H-benzo[1,4]oxazin-3-one (39.0 g, 82%) as yellow oil. Rf (hexane/EtOAc 5:2) 0.45. 1H-NMR (400 MHz, CDCl3) 1.55 (s), 1.91-2.02 (m, 2 H), 3.36 (s), 3.43 (t, J=6.0), 4.07 (t, J=6.0), 7.04 (d, J=9.0), 7.93 (dd, J=9.0, 0.4), 8.09 (d, J=0.4). 13C-NMR (100 MHz, CDCl3) 167.6 (s), 148.9 (s), 143.0 (s), 129.5 (s), 119.8 (d), 117.7 (d), 110.4 (d), 78.9 (s), 69.4 (t), 58.7 (q), 39.7 (t), 27.5 (t), 23.7 (2q).

Provenance & Evidence