反应详情

Pyrazine-2-carbonitrile (26.36 g) is dissolved in toluene (187 ml)/N,N-dimethylformamide (19 ml), and thereto is added dropwise sulfuryl chloride (135 g) under ice-cooling. After completion of addition, the reaction solution is warmed to room temperature gradually and stirred overnight. The toluene layer is separated and the residual red oil is extracted with diethyl ether. The organic layers are combined, cooled with ice, and after pouring thereto ice-water, neutralized by adding saturated aqueous sodium hydrogen carbonate solution. The organic layer is separated, and aqueous layer is extracted with diethyl ether. The organic layers are combined, washed with water, dried over sodium sulfate and evaporated to remove the solvent under reduced pressure. The resulting residue is purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=4/1) to give the title compound (16.58 g).

1. temperaturecooling
2. additionAfter completion of addition
3. customThe toluene layer is separated
4. extractionthe residual red oil is extracted with diethyl ether
5. temperaturecooled with ice
6. additionafter pouring
7. additionby adding saturated aqueous sodium hydrogen carbonate solution
8. customThe organic layer is separated
9. extractionaqueous layer is extracted with diethyl ether
10. washwashed with water
11. dry with materialdried over sodium sulfate
12. customevaporated
13. customto remove the solvent under reduced pressure
14. customThe resulting residue is purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=4/1)