反应详情

Pyridiniumchlorochromate (9.36 g, 43.4 mmol) was added to the solution of the crude N-(4,5-difluoro-2-(hydroxymethyl)phenyl)pivalamide in CH2Cl2 (150 mL) at rt. The yellow solution turned into dark brown in 10 min, and the mixture was continued stirring for 3 hr, and then passed through a thin silica gel pad with CH2Cl2 (2×50 mL). The combined organic solution was concentrated on rotary vacuum, and purified on flash chromatography eluting with 20˜60% EtOAc/hexanes (1300 mL) to afford the expected product as a brown solid (1.91 g, 26% yield after three step); 1H NMR (400 MHz, CDCl3) δ ppm 1.29 (s, 9 H), 7.42-7.48 (m, 1 H), 8.75 (dd, J=13.35, 7.30 Hz, 1 H), 9.77-9.80 (m, 1 H), 11.40 (s, 1 H); Mass spec. 242.08 (MH+), Calc. for C12H13F2NO2 241.09.

1. customdark brown in 10 min
2. concentrationThe combined organic solution was concentrated on rotary vacuum
3. custompurified on flash chromatography
4. washeluting with 20˜60% EtOAc/hexanes (1300 mL)