反应详情

Phosgene is introduced at 40°-50° C., after the addition of 20 parts of pyridine, into a solution of 10 parts of 2-amino-3-hydroxy-5-chloropyridine in 200 parts of chloroform, and stirring is maintained for one hour at room temperature; the chloroform and the pyridine are evaporated off in a water-jet vacuum, and ice-water is added to the residue. The precipitate is filtered off and dried at 40°-50° C. in vacuo. There are obtained 10 parts of 6-chloro-oxazolo[4,5-b]pyridin-2-(3H)-one (85% of theory), m.p. 184°-186° C.

1. customthe chloroform and the pyridine are evaporated off in a water-jet vacuum, and ice-water
2. additionis added to the residue
3. filtrationThe precipitate is filtered off
4. customdried at 40°-50° C. in vacuo