반응 #87330

반응 방정식

calcium hydroxide

2-chloro-6-methylpyrazine

ethanol

potassium peroxodisulfate

→

title compound

6-Methylpyrazine-2-ol-1-oxide

용매

sulfuric acid

ethanol tetrahydrofuran

반응 조건

후처리

1. 1
   여과filtered off
2. 2
   세척washed with ethanol
3. 3
   기타The filtrate was evaporated until dryness
4. 4
   온도the obtained solid (20 g) were refluxed in 300 ml 20% KOH solution for 3 h
5. 5
   온도after cooling pH 3
6. 6
   기타The solution was evaporated until dryness
7. 7
   온도under reflux for 2 h
8. 8
   온도after cooling
9. 9
   여과filtered
10. 10
    기타the filtrate evaporated until dryness

실험 절차

156 mmol (20 g) 2-chloro-6-methylpyrazine were dissolved in 80 ml 96% sulfuric acid, 222 mmol (63 g) potassium peroxodisulfate were added portion wise at 10° C. and stirring was carried out for 2 days at 10° C. and 1 day at room temperature (see also C. E. Mixan, R. Garth, J. Org. Chem. 1977, 42, 1869-1871). The reaction mixture was poured on 200 g ice, under addition of ethanol neutralization was carried out with calcium hydroxide, then filtered off and washed with ethanol. The filtrate was evaporated until dryness, the obtained solid (20 g) were refluxed in 300 ml 20% KOH solution for 3 h and after cooling pH 3 was adjusted with 20% HCl. The solution was evaporated until dryness, the residue boiled with 0.2 l ethanol under reflux for 2 h, after cooling filtered and the filtrate evaporated until dryness. After recrystallization from ethanol/tetrahydrofuran from 7.4 g raw product 2.17 g (10% yield, 93% purity) of the title compound were obtained.

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