Synthesis
GENERAL STEPS: NaH (60% dispersed in mineral oil, 40.00 mmol, 0.96 g) was added in batches to a stirred solution of 3-indolecarboxaldehyde (20.00 mmol, 2.90 g) in anhydrous THF (50 mL) under ice bath cooling conditions. After slowly warming to room temperature, stirring was continued for 30 min. Subsequently, anhydrous THF solution of benzenesulfonyl chloride (24.00 mmol, 4.24 g) was added dropwise. The progress of the reaction was monitored by TLC and after complete disappearance of the raw material 3-indolecarboxaldehyde, the solvent was removed by evaporation under reduced pressure. The reaction mixture was diluted with ice water (300 mL) and the solid product was collected by filtration. Recrystallization with acetone/petroleum ether (60-90 °C) afforded the target product 1-(phenylsulfonyl)-3-indolecarboxaldehyde in 97% yield, melting point 151-153 °C. 1H NMR (600 MHz, CDCl3): δ 7.37 (t, J = 7.2 Hz, 1H), 7.42 (dd, J = 11.4, 4.2 Hz, 1H), 7.52 (t, J = 7.8 Hz, 2H), 7.62 (t, J = 7.2 Hz, 1H), 7.97 (t, J = 7.8 Hz, 3H), 8.20-8.31 (m, 2H), 10.11 (s, 1H). HRMS (MALDI): m/z 286.0515. calculated value C15H11NO3S: [M + H]+ 286.0538.
References
[1] Synlett, 1999, # 6, p. 786 - 788
[2] European Journal of Medicinal Chemistry, 2012, vol. 53, p. 283 - 291
[3] Journal of Organic Chemistry, 2002, vol. 67, # 3, p. 1001 - 1003
[4] Synthetic Communications, 2007, vol. 37, # 5, p. 829 - 837
[5] Tetrahedron, 1998, vol. 54, # 46, p. 13915 - 13928
