反应详情

温度

60 °C

A solution of diethylamine hydrochloride (3.82 g, 35 mmol) and triethylamine (0.23 ml) in ethanol (1.75 ml) and water (1.75 ml) was added dropwise, at 60° C., to a mixture of 2-methyl-quinoxaline (5.0 g, 35 mmol), formaldehyde (2.81 g of 37% solution, 35 mmol), triethylamine (0.17 ml) and ethanol (4.6 ml). The pH was adjusted to 7–7.5 by mean of dilute aqueous hydrochloric acid. Stirring was maintained 16 hours at 60° C. The solvent was concentrated, the residue was diluted with water and extracted with diethyl ether to remove the unreacted quinoxaline. The aqueous phase was basified with 20% aqueous sodium hydroxide (10 ml) and extracted with ethyl acetate. The organic phase was dried over magnesium sulfate and concentrated. The residue was chromatographed on silica gel eluting with dichloromethane-methanol (first 95-5 then 90-10 and finally 90-10 plus 0.1% of ammonia) to give diethyl-(2-quinoxalin-2-yl-ethyl)-amine (2.67 g, 37%).

1. concentrationThe solvent was concentrated
2. additionthe residue was diluted with water
3. extractionextracted with diethyl ether
4. customto remove the unreacted quinoxaline
5. extractionextracted with ethyl acetate
6. dry with materialThe organic phase was dried over magnesium sulfate
7. concentrationconcentrated
8. customThe residue was chromatographed on silica gel eluting with dichloromethane-methanol (first 95-5