反应详情

温度

80 °C

5.2 g of 2,3-diaminopyridine in 209 g of polyphosphoric acid are heated at 120° C. for 0.5 h. The solution is cooled to 80° C. and 4.6 ml of 2-chloropropionitrile are added. Thereafter, the reaction mixture is heated to 180° C. for 2.5 h. After cooling, the polyphosphoric acid is hydrolysed with 150 ml of water. After reheating to 90° C., charcoal is added under vigorous stirring. Subsequently, the suspension is filtered through a celite pad while still hot (70° C.). The filter cake is rinsed with 100 ml of water and the pH value of the filtrate is adjusted to pH 4 using 9 M aqueous sodium hydroxide solution. The mixture is extracted twice each with 250 ml of ethyl acetate, the combined organic phases are dried using sodium sulfate, concentrated and lyophilized from ethanol/water to give 3.56 g of the title compound as a light brown, amorphous solid. MS: 182.2/184.2 (MH+, 100%/32%). M.p. 132° C. TLC: Rf=0.60 (dichloromethane/methanol 8:1).

1. temperatureThereafter, the reaction mixture is heated to 180° C. for 2.5 h
2. temperatureAfter cooling
3. customAfter reheating to 90° C.
4. filtrationSubsequently, the suspension is filtered through a celite pad while still hot (70° C.)
5. washThe filter cake is rinsed with 100 ml of water
6. extractionThe mixture is extracted twice each with 250 ml of ethyl acetate
7. customthe combined organic phases are dried
8. concentrationconcentrated