反应详情

In a 500 mL pear flask was added 1-ethyl-1H-pyrrolo[3,2-c]pyridine-6-carboxylic acid (1G, assumed 30.4 mmol) in dioxane (90 ml) and t-butanol (90 ml) to give a brown suspension. To this was then added triethylamine (5.5 ml, 40 mmol) and the mixture was then heated to 85° C. After 7 hours, the reaction did not change much from the 25% conversion achieved in the first two hours. An additional 4.3 ml of diphenylphosphoryl azide (0.65 eq.) was added the next morning and after 5 hours, the reaction has progressed significantly. Brine was added and the mixture was extracted twice with ethyl acetate. Combined organic layers were dried over MgSO4, filtered and concentrated. Crude product was purified by column chromatography (SiO2, eluting with a gradient of 20-30% EtOAc/hexanes) to give tert-butyl 1-ethyl-1H-pyrrolo[3,2-c]pyridin-6-ylcarbamate (1H, 3.6 g, 45%).

1. customto give a brown suspension
2. customachieved in the first two hours
3. waitafter 5 hours
4. extractionthe mixture was extracted twice with ethyl acetate
5. dry with materialCombined organic layers were dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. customCrude product was purified by column chromatography (SiO2
9. washeluting with a gradient of 20-30% EtOAc/hexanes)