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

HRID 1698339Notes

Reaction equation

[NH2:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[CH:4][C:3]=1[OH:11].Br[C:13]([CH3:20])([CH3:19])[C:14](OCC)=[O:15].[F-].[K+].O>CN(C=O)C>[CH3:19][C:13]1([CH3:20])[C:14](=[O:15])[NH:1][C:2]2[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[CH:4][C:3]=2[O:11]1

Participants

Conditions

Temperature: 60 °C

Procedure

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).

Workup

stirringstirred for 48 h
filtrationthe resulting precipitate is collected by filtration
washwashed with H2O and Et2O for several times respectively

Sources & evidence

ORD record: ord-68399c2e84194016a038aaee9677ee75
Source dataset: uspto-grants-2012_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08163773B2

Reaction notes

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