反应详情

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

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