反应详情

To a flask containing Dowtherm™ A (500 mL) at 250° C. was added ethyl 3-(6-chloropyridin-3-ylamino)-2-(methylsulfonyl)acrylate (8.2 g, 30 mmol) portion wise over 3 to 5 min and the reaction mixture was stirred for an additional 30 to 45 min. The reaction mixture was removed from the heat source, cooled to room temperature and diluted with hexanes to facilitate precipitation. The solids were collected by filtration, filtered, washed with hexanes and dried under vacuum to afford the intermediate 6-chloro-3-(methylsulfonyl)-1,5-naphthyridin-4-ol which was stirred with heat at 70° C. in neat phosphorus oxychloride (31 mL) with catalytic N,N-dimethylformamide for 4 h. The reaction was cooled and poured slowly into a vigorously stirring mixture of ice-cold satd. aq. sodium bicarbonate and ethyl acetate. The layers were separated and the organic layer was dried over sodium sulfate, filtered and concentrated. The residue was purified by chromatography (silica, hexanes/ethyl acetate) to provide the desired product (2.7 g, 33% over two steps) as a brown solid: 1H NMR (500 MHz, CDCl3) δ 9.50 (s, 1H), 8.46 (d, J=8.8 Hz, 1H), 7.83 (d, J=8.8 Hz, 1H), 3.41 (s, 3H); ESI MS m/z 278 [M+H]+.

1. customThe reaction mixture was removed from the heat source
2. additiondiluted with hexanes
3. customprecipitation
4. filtrationThe solids were collected by filtration
5. filtrationfiltered
6. washwashed with hexanes
7. customdried under vacuum