4-Chloro-5-fluoroindole

Synthesis

The general procedure for the synthesis of 4-chloro-5-fluoroindole using the compound (CAS: 908600-95-3) as starting material was as follows: tetrabutylammonium fluoride hydrate (1.9 g, 7.38 mmol) was dissolved in THF (30 mL) along with compound 2 (1.2 g, 3.69 mmol), and the reaction was stirred for 30 min at room temperature. After completion of the reaction, the reaction mixture was diluted with ether (30 mL), followed by washing with brine (30 mL), drying with anhydrous sodium sulfate, filtering to remove the desiccant, and the filtrate was concentrated under reduced pressure to remove the solvent. Finally, purification by column chromatography (eluent: petroleum ether/ethyl acetate = 50:1) afforded compound 3 (0.5 g, 80.1% yield) as a brown oil.

References

[1] European Journal of Organic Chemistry, 2006, # 13, p. 2956 - 2969
[2] Patent: US2016/9706, 2016, A1. Location in patent: Paragraph 0354; 0357