反应详情

温度

95 °C

1,8-diazabicyclo[5.4.0]undec-7-ene (DBU; 14.4 g, 0.0944 mol) is added to a mixture of 2-(2,4,6-triflorophenyl)malonic acid diethyl ester (14.3 g, 0.0472 mol) and pyrazine-2-carboxamidine hydrochloride (9.00 g, 0.0566 mol) in 1-methyl-2-pyrrolidinone (NMP; 50 mL) solvent. The resulting mixture is heated to 95° C. while stirring for 7 hours. The mixture is cooled to about 50° C. and then HCl solution (37%, 5.6 mL) is added dropwise, keeping the temperature below 50° C. The mixture is then allowed to cool to about 20° C. Water (50 mL) is added dropwise over 20 minutes, causing the product to precipitate as a solid from the mixture (20–25° C.). The solid is collected by filtration, and the product cake is washed with water (300 mL). The solid is allowed to dry at 23° C. under atmospheric pressure for 24 hours, giving a yellow solid (11.5 g, 97% HPLC area, 76% yield. 1H NMR (DMSO-d6): d 12.45 (bs, 2H), 9.41 (s,1H), 8.91(s,1H), 8.46(m, 1H), 7.23(m, 2H).

1. temperatureThe mixture is cooled to about 50° C.
2. customthe temperature below 50° C
3. temperatureto cool to about 20° C
4. customto precipitate as a solid from the mixture (20–25° C.)
5. filtrationThe solid is collected by filtration
6. washthe product cake is washed with water (300 mL)
7. customto dry at 23° C. under atmospheric pressure for 24 hours
8. customgiving a yellow solid (11.5 g, 97% HPLC area, 76% yield