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Paper | Regular issue | Vol 81, No. 11, 2010, pp.2555-2567
Published online, 2nd September, 2010
DOI: 10.3987/COM-10-12029
Synthesis of 1-Azaxanthones and 1-Azathioxanthones by Yb(OTf)3/TfOH Co-Catalyzed Intramolecular Friedel-Crafts Reaction

Jie Li, Can Jin, and Weike Su*

*Key Laboratory of Pharmaceutical Engineering of Ministry of Educations, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China

Abstract

Intramolecular Friedel-Crafts cyclization of phenoxypyridine acids (1a-1j) and phenythiopyridine acids (3a-3i) to form 1-azaxanthones (2a-2j) and 1-azathioxanthones (4a-4i), respectively, was efficiently promoted by Yb(OTf)3/TfOH as co-catalysts. And a number of substrates could be cyclized in moderate to good yields.