反应详情

温度

80 °C

2-Bromobenzenamine (18.77 g) in 50 ml of conc HCl and 50 ml of water, was cooled in an ice bath and treated dropwise with stirring with a solution of sodium nitrite (8.28 g) in water (35 ml). After the addition was complete, the mixture was stirred in the ice bath for a further 30 minutes and then added portionwise (over 5 minutes) to pyridine (275 ml) stirred in an oil bath at 80° C. The mixture was heated (at 80° C.) for a further 1 hour, when the excess of pyridine was distilled off under reduced pressure. The residue was basified (aqueous sodium hydrogen carbonate) and extracted with ethyl acetate (3×). The extracts were washed with water (2×), dried (sodium sulphate) and evaporated to give a dark oil, which was flash chromatographed on silica using methylene chloride/ethyl acetate (20/1) as eluant. Pure sub-title compound (6.56 g) was obtained as a dark brown oil.

1. additiontreated dropwise
2. additionAfter the addition
3. temperatureThe mixture was heated (at 80° C.) for a further 1 hour
4. distillationwhen the excess of pyridine was distilled off under reduced pressure
5. extractionextracted with ethyl acetate (3×)
6. washThe extracts were washed with water (2×)
7. dry with materialdried (sodium sulphate)
8. customevaporated
9. customto give a dark oil, which
10. customchromatographed on silica
11. customwas obtained as a dark brown oil