Synthesis
The general procedure for the synthesis of 5-hydroxyisoquinoline from 5-isoquinolinesulfonic acid is as follows: 23 g of 5-isoquinolinesulfonic acid is added to 400 ml of water, followed by 60 g of sodium hydroxide. The reaction mixture was heated to reflux and stirred continuously under this condition for 24 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the pH was adjusted with dilute hydrochloric acid to 5. Then, ethyl acetate was added for extraction and the organic phase was separated and collected. The organic phase was concentrated and the resulting residue was purified by silica gel column chromatography to yield 16 g of 5-hydroxyisoquinoline.
References
[1] Acta Poloniae Pharmaceutica, 1994, vol. 51, # 6, p. 479 - 482
[2] Patent: CN107778231, 2018, A. Location in patent: Paragraph 0023; 0024
