Synthetic studies in aromatic hemiterpenes of natural origin, Part 5: Synthesis of 6-acetyl-2,2-dimethyl-8-methoxychromene via benzylic oxidation route

Naidu, Venkama M and Rao, Krishna GS (1979) Synthetic studies in aromatic hemiterpenes of natural origin, Part 5: Synthesis of 6-acetyl-2,2-dimethyl-8-methoxychromene via benzylic oxidation route. In: Proceedings og the indian academy of sciences section A , 88 (3). pp. 197-201.

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Abstract

The synthesis of 6-acetyl-2,2-dimethyl-8-methoxychromene (lc), a naturally occurring isomer of encecalin (la)h~s been described startilag from 2,2,6- trimethyl-8-methoxyclaromene (2e) which was obtained from creosol (4) in two steps involving condensation of the phenol with malic acid to the coumarin (3), followed by Grignard reaction with CHaMgI. The transformation of (2e) to the natural product (lc) was effeeted by oxidative dehydrogenation by DDQ of the 6-meth~r function to the formyl group (2f), Grignard reaction to the carbinol (2g) and finally its oxidation to the acetyl moiety (lc), the sequence of the essential steps schematically summarised as : Ar-CHs --* Ar-CHO --* Ar-CH (OH) CHs --* Ar---COCHs.

Item Type:	Journal Article
Publication:	Proceedings og the indian academy of sciences section A
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Aromatic hemiterpenr couma~ins; chromenes; benzylic oxidative dehydrogenation by DDQ.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	27 Dec 2010 13:31
Last Modified:	27 Dec 2010 13:31
URI:	http://eprints.iisc.ac.in/id/eprint/33810

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