反应详情

A stirred solution of 3-aminophenylboronic acid hemisulfate (6.2 g; 33.3 mmol) and 50% H2SO4 (3.7 ml; 33.3 mmol) in H2O (100 ml) at −2° C. was solution of NaNO2 (2.5 g; 36.3 mmol) in H2O (20 ml) over 1 h. The reaction mixture was slowly added to a stirred solution of conc. H2SO4 (25 ml) in H2O (20 ml) at reflux. After complete addition, the reaction mixture was refluxed for 30 min., cooled, added activated charcoal, heated to reflux, cooled and filtered through celite. The filtrate was saturated with NaCl (s), filtered and extracted with Et2O (5×100 ml). The combined organic fractions were dried (Na2SO4) and evaporated to dryness to give 4.3 g (94%) product.

1. customat −2° C.
2. customover 1 h
3. temperatureat reflux
4. additionAfter complete addition
5. temperaturethe reaction mixture was refluxed for 30 min.
6. temperaturecooled
7. additionadded
8. temperatureheated
9. temperatureto reflux
10. temperaturecooled
11. filtrationfiltered through celite
12. filtrationfiltered
13. extractionextracted with Et2O (5×100 ml)
14. dry with materialThe combined organic fractions were dried (Na2SO4)
15. customevaporated to dryness