Water → 6-nitro-4-propargyl-2H-1,4-benzoxazin-3(4H)-one

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Reaction Conditions

Reaction Steps

While kept under N2, 0.81 g (20 mmol) of sodium hydride (60% dispersion in oil) was washed with 3 ml of pentanes and suspended in 20 ml of anhydrous dimethylformamide. While cooling with an ice/brine bath, 3.59 g (18.5 mmol) of 6-nitro-2H-1,4-benzoxazin-3(4H)-one was added through a dry powder funnel (exotherm of about 5° C.). An additional 10 ml of DMF was added and the mixture was stirred at 0° C. for 30 minutes. There was then added 2.06 ml (18.5 mmol) of an 80% solution of propargyl bromide in toluene and the mixture was stirred at room temperature for 12 hrs. The reaction mixture was poured into 50 ml of water and extracted with EtOAc (2×50 ml). The organic layers were combined, washed with water (2×50 ml) and dried (MgSO4). The solvent was removed in vacuo to yield 6-nitro-4-propargyl-2H-1,4-benzoxazin-3(4H)-one as a yellow solid, 4 g (93% yield).

Provenance & Evidence