4-Nitro-2-(trifluoromethyl)-1,3-benzoxazole → 2-(Trifluoromethyl)-4-benzoxazolamine

Participants

Reaction Conditions

Reaction Steps

Compound 476A (10.75 g, 46.30 mmol) was dissolved in 1:1 EtOAc/10% HOAc (250 mL) and heated to 65° C. Iron powder (12.93 g, 231.5 mmol) was added portionwise and the reaction was stirred for 6 h at 65° C. After cooling, the mixture was filtered through Celite rinsing with EtOAc. The organic layer was separated, washed with H2O (3×100 mL), brine (100 mL), dried over MgSO4, and concentrated in vacuo to give a brown oil. The crude material was purified by flash chromatography on silica gel eluting with 70/30 CH2Cl2/hexanes to give compound 476B (7.02 g, 75%) as a yellow crystalline solid. HPLC: 96.7% at 2.68 min (retention time) (YMC S5 ODS column, 4.6×50 mm, eluting with 10-90% aqueous methanol over 4 mincontaining 0.2% phosphoric acid, 4 mL/min, monitoring at 220 nm).

Provenance & Evidence