反应详情

65 ml of fuming nitric acid (d =1.5) were added dropwise while cooling to 210 ml of concentrated sulfuric acid. 96.5 g of 2.3.5-trimethylpyridine 1-oxide were subsequently added portionwise at 0-5° , whereupon the mixture was stirred at room temperature for 1 hour, then heated to 90° within 3 hours and left at this temperature overnight. After cooling the solution was poured on to 1.5 kg of ice. whereupon the mixture was adjusted to pH 3 with concentrated sodium hydroxide solution and extracted three times with 500 ml of methylene chloride. The combined organic phases were washed with 1 1 of water, dried over sodium sulfate and evaporated in vacuo. The residue was crystallized from ether/petroleum ether and there was obtained 2,3,5-trimethyl-4-nitropyridine 1-oxide of melting point 76-78° .

1. temperatureheated to 90° within 3 hours
2. waitleft at this temperature overnight
3. temperatureAfter cooling the solution
4. extractionextracted three times with 500 ml of methylene chloride
5. washThe combined organic phases were washed with 1 1 of water
6. dry with materialdried over sodium sulfate
7. customevaporated in vacuo
8. customThe residue was crystallized from ether/petroleum ether