反应详情

Charge a 125 mL round-bottomed flask with 2-chloro-6-hydrazinylpyridine (3.0 g, 20.9 mmol), triethoxymethane (20 mL, 120.2 mmol). The mixture was heated at reflux for 4 hours and allowed to cool to ambient temperature overnight. The mixture was concentrated to dryness and 50 ml POCl3 was added. The mixture was refluxed overnight. The reaction was quenched over ice and washed with CH2Cl2. The aqueous layer was adjusted to pH 6 with 1N NaOH and extracted with CH2Cl2 and the organics concentrated and purified on Si gel eluting with 100% EtOAc (500 ml) followed by 5% MeOH/CH2Cl2 to give 5-chloro-[1,2,4]triazolo[4,3-a]pyridine (1.73 g, 11.25 mmol, 53% yield) as a solid.

1. temperatureThe mixture was heated
2. temperatureat reflux for 4 hours
3. concentrationThe mixture was concentrated to dryness and 50 ml POCl3
4. additionwas added
5. temperatureThe mixture was refluxed overnight
6. customThe reaction was quenched over ice
7. washwashed with CH2Cl2
8. extractionextracted with CH2Cl2
9. concentrationthe organics concentrated
10. custompurified on Si gel
11. washeluting with 100% EtOAc (500 ml)