反应详情

A mixture of 17.3 g (66.2 mmol) of 1,4-dihydroxy-isoquinoline-3-carboxylic acid butyl ester and 100 ml of phosphorous oxychloride was stirred at ambient temperature for 1 h, and then heated slowly with stirring in the course of 2 h to reflux temperature. The mixture was refluxed gently with stirring for 30 min. After cooling to room temperature the excess phosphorous oxychloride was evaporated in vacuo, and the residue was dissolved in 100 ml of ethyl acetate The solution was poured into 300 ml of a saturated aqueous sodium bicarbonate solution with stirring. The precipitate formed was removed by vacuum filtration. The organic phase was separated, and the aqueous phase was extracted with 3×100 ml of ethyl acetate. The combined aqueous phases were dried over sodium sulfate, filtered through a pad of silica gel and evaporated in vacuo to give a brown oil that solidified later. 11.37 g of the title compound were obtained; 1H NMR (CDCl3): δ=11.91 (s, 1H), 8.41 (m, 1H), 8.29 (m, 1H), 7.83 (m, 2H), 4.49 (t, 2H), 1.84 (m, 2H), 1.48 (m, 2H), 0.99 (t, 3H).

1. temperatureheated slowly
2. stirringwith stirring in the course of 2 h
3. temperatureto reflux temperature
4. temperatureThe mixture was refluxed gently
5. stirringwith stirring for 30 min
6. customwas evaporated in vacuo
7. dissolutionthe residue was dissolved in 100 ml of ethyl acetate The solution
8. additionwas poured into 300 ml of a saturated aqueous sodium bicarbonate solution
9. stirringwith stirring
10. customThe precipitate formed
11. customwas removed by vacuum filtration
12. customThe organic phase was separated
13. extractionthe aqueous phase was extracted with 3×100 ml of ethyl acetate
14. dry with materialThe combined aqueous phases were dried over sodium sulfate
15. filtrationfiltered through a pad of silica gel
16. customevaporated in vacuo
17. customto give a brown oil that