5-Bromo-8-nitroisoquinoline

Uses

5-Bromo-8-nitroisoquinoline is mainly used as an intermediate in organic synthesis and pharmaceutical chemistry, and can be used in the synthesis of drug molecules, pesticides, and dyes. In organic synthesis transformations, the bromine atom in 5-bromo-8-nitroisoquinoline can undergo debromination and hydrochemical oxidation under palladium and hydrogen conditions; in addition, the nitrogen atom on the isoquinoline ring can be oxidized to nitrogen oxides under the action of appropriate oxidizing agents.

Chemical Properties

It is light yellow solid powder under normal temperature and pressure, with certain alkalinity, can form salt with various acids.

Synthesis

Example 2: An aqueous solution of potassium nitrate (1.78 g, 8.56 mmol) was slowly added dropwise to a solution of 5-bromoisoquinoline dissolved in 12 mL of concentrated sulfuric acid. The reaction mixture was stirred at room temperature for 3 hours before it was poured into ice water and neutralized with concentrated ammonium hydroxide solution. The resulting yellow precipitate was extracted by ethyl acetate (3 x 10 mL) and the combined organic layers were washed with saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After filtration, the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford 5-bromo-8-nitroisoquinoline in 96% yield using a hexane solution of 40% ethyl acetate as eluent.

References

[1] Patent: WO2004/76424, 2004, A1. Location in patent: Page 174-175
[2] Patent: EP698025, 1997, B1
[3] Patent: US5917053, 1999, A
[4] Patent: US5436250, 1995, A
[5] Patent: EP633262, 1995, A1