Synthesis
The general procedure for the synthesis of 5-chloro-3-indoleacetophenone from 5-chloroindole and ethanoic anhydride: 1 mmol of 5-chloroindole, 1 mmol of ethanoic anhydride, 0.01 mmol of metal salt catalyst of trifluoromethanesulfonic acid, and 1 mmol of ionic liquid were sequentially added to a 10 mL glass reaction tube suitable for single mode microwave reaction. Subsequently, the reaction tube was sealed with a polytetrafluoroethylene cap and placed in a single-mode microwave reactor, and the microwave radiation reaction was carried out under different temperature and time conditions to optimize the reaction conditions. After completion of the reaction, the reaction tube was cooled to room temperature and the reaction mixture was extracted with ether (5 × 10 mL). The ether layer was separated and washed with deionized water (2 × 10 mL), saturated aqueous sodium bicarbonate solution (2 × 20 mL) and saturated saline (2 × 10 mL) sequentially. The organic phase was dried over anhydrous magnesium sulfate and filtered, and concentrated under reduced pressure to remove the solvent. The crude product was purified by fast column chromatography (silica gel, n-hexane/ethyl acetate, gradient elution ratio from 10:0 to 8:2) to obtain the target product 5-chloro-3-indoleacetophenone, and the isolated yield was calculated.
References
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