Nuclear methylation of chalkones and flavanones
R N Goel A C Jain T R Seshadri
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Nuclear methylation of 2:4-dihydroxy-chalkones (III) give rise to 3-C-methyl derivatives just as in the case of resacetophenone. C-Methylchalkone-derivatives (IV) with substituents in the side phenyl nucleus have also been prepared by this method. For comparison, they have been synthesised using 3-methyl-peonol and appropriate derivatives of benzaldehyde. C-Methyl-iso-liquiritigenin-dimethyl-ether (IVb) was cyclised to the corresponding 8-methyl-flavanone (VI).
The flavanone, naringenin, when subjected to nuclear methylation under mild conditions yields 6-methyl-flavanone derivative (VIII) whereas under conditions in which the oxygen ring opens, beside the above 6-methyl flavanone (VIII), poly-C-methylated chalkones (XIIa+b) are formed just as in case of phloracetophenone.
R N Goel1 A C Jain1 T R Seshadri1
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