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Communication | Regular issue | Vol 26, No. 2, 1987, pp.319-323
Published online, 1st January, 1970
DOI: 10.3987/R-1987-02-0319
Claisen Rearrangement of 5- or 7-Propargyloxyflavones: Formation of Pyranoflavones

Kode Nagesware Rao and Gotety Srimannarayana

*Department of Chemistry, Osmania University, Hyderabad 500 007, India


The Claisen rearrangement of 7-propargyloxy-5-hydroxy-3-phenylflavone, 7-propargyloxy-5-hydroxy-3-methylflavone and 7-methoxy-5-propargyloxy- 3-methylflavone in N,N-dimethylaniline at 195°C resulted in the formation of angular 2H-[1]-pyranoflavones, 2,3-diphenyl-5-hydroxy-8H-4-oxobenzo-[1,2-b:5,6-b’]dipyran, 5-hydroxy-3-methyl-2-phenyl- 8H-4-oxobenzo-[1,2-b:5,6-b’]dipyran and 9-methoxy-3-methyl- 2-phenyl-6H-4-oxobeno-[1,2-b:3,4-b’]dipyran, respectively in 50% yields. The structures were determined by spectral characteristics.