反应详情

温度

130 °C

The material from Step 2 (1 g) was dissolved in phosphoric acid (20 ml), then added to formic acid (10 ml) and heated (130° C.) for 1 h, and then cooled to RT for 3 d. The reaction mixture was then poured into ice (200 g) and the pH adjusted with 30% (w/v) aq. NaOH until solids formed. The solids were removed via filtration and rinsed with water. The filtrate (aqueous) was concentrated to dryness and extracted with hot EtOH repeatedly. The EtOH extracts were combined and concentrated to solids (3 g). The solids were extracted with hot MeCN (4×80 ml); the combined MeCN extracts were cooled to RT and solids precipitated. The precipitates were filtered (Celite) and the filtrate was concentrated to yield 6-chloro-7-methyl-3H-imidazo[4,5-b]pyridine (0.278 g). MS (ESI+) for m/z 168 (M+H)+.

1. temperaturecooled to RT for 3 d
2. customformed
3. customThe solids were removed via filtration
4. washrinsed with water
5. concentrationThe filtrate (aqueous) was concentrated to dryness
6. extractionextracted with hot EtOH repeatedly
7. concentrationconcentrated to solids (3 g)
8. extractionThe solids were extracted with hot MeCN (4×80 ml)
9. temperaturethe combined MeCN extracts were cooled to RT
10. customsolids precipitated
11. filtrationThe precipitates were filtered (Celite)
12. concentrationthe filtrate was concentrated