Synlett 2011(13): 1930-1936  
DOI: 10.1055/s-0030-1260968
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Efficient Copper-Catalyzed Synthesis of Fused Pyridoquinazolones

Lujun Chena,b, Hua Fu*a, Renzhong Qiao*b
a Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, P. R. of China
Fax: +86(10)62781695; e-Mail: fuhua@mail.tsinghua.edu.cn;
b State Key Laboratory of Chemical Resource Engineering, Department of Pharmaceutical Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, P. R. of China
e-Mail: qiaorz@mail.buct.edu.cn;
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Publikationsverlauf

Received 18 April 2011
Publikationsdatum:
21. Juli 2011 (online)

Abstract

A simple and efficient copper-catalyzed method for synthesis of fused pyridoquinazolones has been developed without ­addition of any ligand or additive, and it can tolerate various functional groups.

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General Procedure for the Synthesis of Compounds 2a-n A two-necked, round-bottom flask was charged with a magnetic stirrer, evacuated, and back-filled with nitrogen. Substituted 2-halo-N-(pyridin-2-yl)arylamide (1) (0.5 mmol), Cs2CO3 (1 mmol, 326 mg), and toluene (2 mL) were added to the flask. After a 10 min stirring at r.t. under nitrogen atmosphere, CuI (0.025 mmol, 5 mg) was added to the flask. The mixture was stirred at 110 ˚C for 24 or 36 h (see Table  [²] in text) under nitrogen atmosphere. After completion of the reaction, the solvent of the resulting mixture was removed with the aid of a rotary evaporator, and the residue was purified by column chromatography on silica gel using PE-EtOAc as eluent to give the desired product.