反应详情

A solution of acetylpyrazine (5 g, 40.9 mmol) in N,N-dimethylformamide dimethyl acetal (10.9 mL, 81.8 mmol) and Et3N (5.7 mL) was heated at 110° C. for 16 h. The heating was stopped and a precipitate was formed while it was allowed to cool down to room temperature. The suspension was diluted with tert-butyl methyl ether; the solid was separated by filtration and washed with tert-butyl methyl ether. This material was triturated with the same solvent, filtered off and dried to afford the title compound 23a as a yellow solid (5.9 g, 33.3 mmol, 81% yield). 1H NMR (400 MHz, DMSO-d6) δ (ppm): 9.09 (s, 1H), 8.73 (d, J=2.4 Hz, 1H), 8.66 (dd, J=2.4, 1.6 Hz, 1H), 7.84 (d, J=12.4 Hz, 1H), 6.30-6.20 (m, 1H), 3.19 (s, 3H), 2.93 (s, 3H).

1. customa precipitate was formed while it
2. customthe solid was separated by filtration
3. washwashed with tert-butyl methyl ether
4. customThis material was triturated with the same solvent
5. filtrationfiltered off
6. customdried