Potassium Carbonate → 3-Methyl-5-nitro-1,2-benzoxazole

Participants

Reaction Steps

To a stirred suspension of 2-(1-iminoethyl)-4-nitrophenol (Step 33.1) (2.94 g, 16.32 mmol) in THF (40 mL) was added N-chlorosuccinimide (3.27 g, 24.48 mmol) and K2CO3 (4.51 g, 32.6 mmol) under Ar. The reaction mixture was stirred for 3 hr at rt, quenched with brine, and extracted with EtOAc. The combined organic layers were washed with a saturated aq. NaHCO3 solution, dried over Na2SO4 and evaporated. The crude product was purified by silica gel column chromatography (hexane/EtOAc 5-15%) to afford the title product (2.8 g, 15.72 mmol, 96% yield) as a white solid. tR: 4.31 min (HPLC 1); tR: 0.86 min (LC-MS 2); ESI-MS: 179 [M+H]+ (LC-MS 2); Rf=0.85 (hexane/EtOAc 1:1).

Provenance & Evidence