反应详情

温度

170 °C

A mixture of 6.5 parts of 2-amino-3,5-dibromopyridine, 12 parts of potassium hydroxide (85%), 0.5 part of copper powder and 100 parts of water is stirred under nitrogen in an autoclave for 10 hours at 170° C. The dark-coloured solution is neutralised with concentrated hydrochloric acid, saturated with sodium chloride and extracted three times in the warm state with an ethyl acetate/tetrahydrofuran mixture (9:1). The combined organic extracts are filtered through Hyflo, dried with sodium sulphate and filtered. After the solvent has been evaporated off, the residue is taken up in a small amount of hot ethyl acetate and chromatographed through silica gel. After removal of the ethyl acetate, there are obtained 2.2 parts (46.3% of theory) of 2-amino-3-hydroxy-5-bromopyridine, m.p. 205°-208° C.

1. extractionextracted three times in the warm state with an ethyl acetate/tetrahydrofuran mixture (9:1)
2. filtrationThe combined organic extracts are filtered through Hyflo
3. dry with materialdried with sodium sulphate
4. filtrationfiltered
5. customAfter the solvent has been evaporated off
6. customchromatographed through silica gel
7. customAfter removal of the ethyl acetate, there