反应详情

A mixture containing 8.16 g (0.04 mol) of 6-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid and 6.2 ml (0.044 mol) of triethylamine in 240 ml of chloroform is cooled below -10° C. by ice-salt. A solution of 4 ml (0.042 mol) of ethyl chloroformate in 20 ml of chloroform is dropped to the above mixture at -15° C. during 20 minutes. After stirring for 5 minutes, 3.835 g (0.044 mol) of n-pentylamine dissolved in 40 ml of chloroform are dropped to the above solution at -15° C. during 20 minutes. The reaction mixture is stirred below -10° C. for 1 hour and then let to stand overnight under cooling by ice. For working up, the reaction mixture is washed 3 times with 100 ml of 5% sodium hydrogen carbonate solution each and then 3 times with 100 ml of water each. The organic phase is dried over anhydrous sodium sulfate, filtered and evaporated to give 6.1 g (55.8%) of the named product as orange yellow crystals after recrystallization from ethanol, m.p.: 112°-116° C.

1. additionare dropped to the above solution at -15° C. during 20 minutes
2. stirringThe reaction mixture is stirred below -10° C. for 1 hour
3. waitto stand overnight
4. temperatureunder cooling by ice
5. washthe reaction mixture is washed 3 times with 100 ml of 5% sodium hydrogen carbonate solution each and then 3 times with 100 ml of water each
6. dry with materialThe organic phase is dried over anhydrous sodium sulfate
7. filtrationfiltered
8. customevaporated