Water → 2,2-Dimethyl-6-nitro-2H-benzo[B][1,4]oxazin-3(4H)-one

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Reaction Conditions

Reaction Steps

At room temperature, a solution of 2-amino-4-nitro-phenol (82.5 g, 0.54 mol) in DMF (660 ml) is treated with ethyl 2-bromoisobutyrate (160 ml, 1.07 mol) and KF (124.7 g, 2.15 mol), stirred at the same temperature for 1 h, warmed to 60° C., and stirred for 48 h. After pouring the mixture into H2O (3500 ml), the resulting precipitate is collected by filtration, and washed with H2O and Et2O for several times respectively to give 2,2-dimethyl-6-nitro-4H-benzo[1,4]oxazin-3-one (84.8 g, 71%) as yellow solid. Rf (hexane/EtOAc 2:1) 0.42. 1H-NMR (400 MHz, DMSO-d6) 1.48 (s), 7.16 (d, J=9.0), 6.42 (d, J=0.4), 8.00 (dd, J=9.0, 0.4). 13C-NMR (100 MHz, DMSO-d6) 167.7 (s), 147.5 (s), 142.0 (s), 128.0 (s), 119.2 (d), 117.3 (d), 110.3 (d), 78.9 (s), 23.7 (2q).

Provenance & Evidence