反应详情

A solution of 2-(3-(tert-butoxycarbonyl)phenyl)-3-methylpyridine-1-oxide (1 eq) and pyridine (4 eq) in acetonitrile (8 vol) was heated to 70° C. A solution of methanesulfonic anhydride (1.5 eq) in MeCN (2 vol) was added over 50 minutes via addition funnel while maintaining the temperature at less than 75° C. The mixture was stirred for an additional 0.5 hours after complete addition. The mixture was then allowed to cool to ambient temperature. Ethanolamine (10 eq) was added via addition funnel. After stirring for 2 hours, water (6 vol) was added, and the mixture was cooled to 10° C. After stirring for 3 hours, the solid was collected by filtration and washed with water (3 vol), 2:1 acetonitrile/water (3 vol), and acetonitrile (2×1.5 vol). The solid was dried to constant weight (less than 1% difference) in a vacuum oven at 50° C. with a slight N2 bleed to afford tert-butyl-3-(6-amino-3-methylpyridin-2-yl)benzoate as a red-yellow solid (53% yield).

1. temperaturewhile maintaining the temperature at less than 75° C
2. additionafter complete addition
3. stirringAfter stirring for 2 hours
4. temperaturethe mixture was cooled to 10° C
5. stirringAfter stirring for 3 hours
6. filtrationthe solid was collected by filtration
7. washwashed with water (3 vol), 2:1 acetonitrile/water (3 vol), and acetonitrile (2×1.5 vol)
8. dry with materialThe solid was dried to constant weight (less than 1% difference) in a vacuum oven at 50° C. with a slight N2