Synthesis
General procedure for the synthesis of 6-chloro-2,3-dihydroinden-1-one from 3-(4-chlorophenyl)propionic acid: trifluoromethanesulfonic acid (3 equiv.) was slowly added to an anhydrous solution of 3-(4-chlorophenyl)propionic acid (0.5 mmol) in anhydrous dichloromethane (1.0 mL) in a 12 mL Q-tube pressure tube (supplied by QLabtech) at 0 °C. . The reaction mixture was then warmed to room temperature. A PTFE septum was placed on top of the reaction tube and sealed using the appropriate cap and pressure adapter. The sealed reaction tube was heated in an oil bath at 80°C. The progress of the reaction was monitored by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC/MS) until the feedstock completely disappeared. After completion of the reaction, the mixture was poured into ice water and extracted three times with dichloromethane. The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. Finally, the target compound 6-chloro-2,3-dihydroinden-1-one was purified from the crude product by fast column chromatography.
References
[1] Molecules, 2014, vol. 19, # 5, p. 5599 - 5610
[2] Patent: WO2017/150904, 2017, A1. Location in patent: Paragraph 402-404
[3] Synthetic Communications, 2007, vol. 37, # 13, p. 2171 - 2177
[4] Bioorganic and Medicinal Chemistry Letters, 2011, vol. 21, # 8, p. 2554 - 2558
[5] Polish Journal of Chemistry, 1991, vol. 65, # 11, p. 2057 - 2060
