ISSN:
0021-8383
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Pyrylium Compounds. XXIX. Substituted Benzophenones from 2,4,6-Triarylpyrylium Salts and Methyl(ene) KetonesIn the presence of piperidine acetate (or similar salts of certain dialkylamines), 2,4,6-triarylpyrylium perchlorates 5 react with methyl(ene) ketones 6 to give benzophenones 7, the structure of which was proved by spectroscopic methods as well as by independent synthesis. Besides acetone and other acyclic ketones (e. g. alkyl methyl ketones, phenylacetone, desoxybenzoin, dibenzyl ketone) cyclic ketones (e. g. cyclopentanone, cyclohexanone, cycloheptanone, acenaphthenone) can also be used as ketone component 6; acetophenones react differently leading to hydrocarbons of the 1,3,5-triarylbenzene type 15. The varying efficiency of the diverse amine salts and the mode of incorporation of the unsymmetrically substituted ketones suggest the intermediate formation of enamines 10 as crucial step of the ring transformations observed. This assumption is supported by isolation of the iminium salt 18 on reacting 3,5-dimethyl-2,4,6-triphenylpyrylium perchlorate (16) with acetone/piperidine acetate.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19853270510
