反应详情

To a solution of diethyl 2-methyloxazolo[5,4-b]pyridine-5,6-dicarboxylate (5.42 g, 0.0195 mol) dissolved in absolute methanol (160 mL) is added a 10% aqueous sodium hydroxide solution (36.1 mL, 0.0974 mol). A white precipitate slowly forms. The reaction is stirred at room temperature for one hour, diluted with water (20 mL) to dissolve the precipitate, and concentrated in vacuo. The residue is dissolved in water and acidified to pH 2-3 with concentrated HCl. The resulting white precipitate is collected by filtration, washed with water, and air dried to give 2-methyloxazolo[5,4-b]pyridine-5,6-dicarboxylic acid in 61% yield, melting point 235°-236° C. (dec).

1. dissolutionto dissolve the precipitate
2. concentrationconcentrated in vacuo
3. dissolutionThe residue is dissolved in water
4. filtrationThe resulting white precipitate is collected by filtration
5. washwashed with water, and air
6. customdried