Synfacts 2007(8): 0891-0891  
DOI: 10.1055/s-2007-968801
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Silica-Supported Acidic Ionic Liquid

Contributor(s): Yasuhiro Uozumi, Yohei Oe
H. Hagiwara*, M. Sekifuji, T. Hoshi, K. Qiao, C. Yokoyama
Niigata University and Tohoku University, Sendai, Japan
Further Information

Publication History

Publication Date:
24 July 2007 (online)

Significance

A new protocol for the synthesis of bis(indolyl)methanes 3 catalyzed by an acidic ionic liquid immobilized on silica (ILIS) under mild reaction conditions was developed. Thus, the reactions of indole 1 with various aldehydes 2 were carried out in the presence of 10 mol% of ILIS-SO2Cl to give the corresponding bis(indolyl)methanes 3 in 65-97% yield. In the reaction of indole 1 with p-chlorobenzaldehyde, the catalyst can be recycled three times without significant loss of catalytic activity decreasing only in the 4th use (yields after 2.5 h; 1st use: 82%; 2nd use: 95%; 3rd use: 98%; 4th use: 78%).