反应详情

Formic acid (18.95 g.) was added dropwise to acetic anhydride (42.0 g.) under stirring at room temperature over 5 minutes, and stirred at 50° C. for an hour. 2-(2-Aminothiazol-4-yl)-2-n-butoxyiminoacetic acid (syn isomer, 25 g.) was added to the solution under ice cooling, and stirred at room temperature for 3 hours and additionally at 30° C. for an hour. After concentrating the resultant solution in vacuo, the residue was dissolved in diethyl ether. The solution was washed with water and a saturated aqueous solution of sodium chloride in turn, dried over magnesium sulfate and concentrated in vacuo. The obtained oil was triturated with a solution of n-hexane (1 part) and diisopropyl ether (1 part), and collected by filtration to give 2-(2-formamidothiazol-4-yl)-2-n-butoxyiminoacetic acid (syn isomer, 20.1 g.).

1. stirringstirred at 50° C. for an hour
2. stirringstirred at room temperature for 3 hours and additionally at 30° C. for an hour
3. concentrationAfter concentrating the resultant solution in vacuo
4. dissolutionthe residue was dissolved in diethyl ether
5. washThe solution was washed with water
6. dry with materiala saturated aqueous solution of sodium chloride in turn, dried over magnesium sulfate
7. concentrationconcentrated in vacuo
8. customThe obtained oil was triturated with a solution of n-hexane (1 part) and diisopropyl ether (1 part)
9. filtrationcollected by filtration