Anthranilic Acid → 2-(3-chlorophenylamino)-6-octyl-4H-3,1-benzoxazin-4-one

Participants

Reaction Steps

The anthranilic acid (200 mg, 0.8 mmol) was dissolved in anhydrous THF (1 ml), and to this was added 3-chlorophenylisocyanate (117 μl, 0.96 mmol). The mixture was stirred for 3 h before being concentrated. The residue was partitioned between water and ethyl acetate. The organic layer was washed with 5% aqueous citric acid, saturated aqueous sodium bicarbonate and brine then dried (MgSO4) and concentrated to give an orange solid. This was purified by flash chromatography on silica (15% EtOAc/hexane to 100% EtOAc, then 10% EtOH/EtOAc) which gave, in order of elution, the benzoxazinone (18 mg, 0.05 mmol); δH (400 MHz, CDCl3) 0.77-0.82 (3H, m, Me), 1.19-1.24 (10H, m, 5×CH2), 1.55-1.57 (2H, m, ArCH2CH2), 2.56-2.62 (2H, m, ArCH2), 7.00-7.32 (4H, m, 3×ArH, NH), 7.40-7.49 (2H, m, 2×ArH), 7.81-7.83 (2H, m, ArH); m/z (ES+) 385 (MH+) and the urea (160 mg, 0.4 mmol); m/z (ES−) 401 (M−H)−.

Provenance & Evidence