Synfacts 2008(8): 0802-0802  
DOI: 10.1055/s-2008-1077937
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Regioselective Synthesis of Chrom-4-ones and Fused Flavones

Contributor(s): Victor Snieckus, Toni Rantanen
M. Xia*, G.-F. Xiang, B. Wu, Y.-F. Han
Zhejiang Sci-Tech University, Hangzhou, P. R. of China
Further Information

Publication History

Publication Date:
23 July 2008 (online)

Significance

Whereas treatment of the α-cyano acetophenone 1 with aromatic aldehydes under Et3N/MeOH conditions leads to the expected Knoevenagel-Michael addition products iso­flavones A and B. Change of solvent to toluene ­results in the polycondensation products X in modest to very good yields. Alternatively, the ­cyanoflavanones A and B can be converted into the condensed flavones X under the same conditions thus establishing precursor/product relationships. The substrate scope was reasonably well studied. Compounds B show intense fluorescent properties with high quantum yields in the range of 0.82-0.87.