反应详情

温度

140 °C

To stirring pyridine (3 mL) was slowly added concentrated hydrochloric acid (3.3 mL). The reaction flask was then fitted for distillation, and water was distilled from the mixture until the temperature rose to 210° C. After cooling to 140° C., 4 (0.241 g, 1.00 mmol) was added to the above mixture, and the reaction flask was fitted with a reflux condenser connected to a N2 source. The yellow mixture was stirred and refluxed for 3 h at 210° C. The resulting reaction mixture was then diluted with warm water (3 mL) and slowly poured into hot water (20 mL). The resulting yellow solution was cooled to room temperature and neutralized with dilute NaOH solution to pH ˜7. The resulting colorless precipitate was then collected by filtration and washed with water to give 0.208 g (91.6%) of analytically pure product as a colorless solid: mp>270° C. (decomp.); 1H NMR (500 MHz, DMSO-d6): δ 9.245 (s, 1H), 8.337 (s, 2H), 6.579 (s, 2H), 1.841 (s, 6H), 1.729 (s, 6H); 13C NMR (125 MHz, DMSO-d6): δ 156.400, 148.191, 147.630, 134.949, 131.015, 127.197, 114.493, 19.359, 16.098; MS (ESI): m/z 228.4 [(M+H)+,100]; Anal. Calcd. For C15H17NO: C, 79.26; H, 7.54; N, 6.16. Found: C, 79.14; H, 7.58; N, 6.18.

1. distillationwas distilled from the mixture until the temperature
2. customrose to 210° C
3. customthe reaction flask was fitted with a reflux condenser
4. temperaturerefluxed for 3 h at 210° C
5. customThe resulting reaction mixture
6. filtrationThe resulting colorless precipitate was then collected by filtration
7. washwashed with water
8. customto give 0.208 g (91.6%) of analytically pure product as a colorless solid