反应详情

To the solution of 28.3 g of 5-aminopyridine-2-carboxylic acid methyl ester in 80 ml of 20% sulfuric acid, cooled to -4°, the solution of 14.31 g of sodium nitrite in 30 ml of water is added dropwise while stirring and maintaining the temperature below 0°. Thereafter the mixture is stirred for 15 minutes below 0° and the mixture of 28 g of potassium thiocyanate and 8 g of cuprous thiocyanate is added portionwise to said solution. Each addition causes evolution of gas and a black oil to separate. With continued stirring the oil again dissolves and the solution is stirred for 3 hours. It is extracted with methylene chloride, the extract filtered and evaporated, to yield the 5-thiocyanatopyridine-2-carboxylic acid methyl ester.

1. temperaturemaintaining the temperature below 0°
2. stirringThereafter the mixture is stirred for 15 minutes below 0°
3. additionis added portionwise
4. additionEach addition
5. customa black oil to separate
6. stirringWith continued stirring the oil
7. dissolutionagain dissolves
8. stirringthe solution is stirred for 3 hours
9. extractionIt is extracted with methylene chloride
10. filtrationthe extract filtered
11. customevaporated