Studies in the Synthesis of Xanthone Derivatives. Part-I Synthesis of Furanoxanthones

Chemistry Department, Faculty of Science, M. S. University of Baroda, Baroda-390 002

Manuscript received 29 Map 1978, accepted 30 August 1978

2-Methylresorcinol, on thermal condensation with ethyl cyclohexanone-2-carboxylate
in diphenyl ether gave 6-hydroxy-5-methyl-1,2,3,4-tetrahydroxanthone, which on
allylation, Claisen migration, cyclisation with conc. sulphuric acid followed by
dehydrogenation with palladised charcoal, gave 4, 5'-dimethylfurano(3', 2'-2,3)xanthone
(III), was also synthesised from 3-hydroxy-4-unethylxanthone by similar series of
reactions. 5'-Methylfurano(2',3'-3,4)xanthone (V) was synthesised, starting from
resorcinol and ethyl cyclohexanone-2-carboxylate and also from 3-hydroxyxanthone.
The structures of intermediate dihydrofuranoxanthones were confirmed by NMR spectra