Green synthetic approaches: solventless synthesis of polyfunctionally substituted aromatics as potential versatile building blocks in organic synthesis utilizing enaminones and enaminonitriles as precursors |
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Abstract: | Abstract A variety of 1,3,5-trisubstituted benzenes could be obtained upon heating enaminones in absence of solvent over montmorillonite-K-10. Heating mixtures of two different enaminones 2a–d have also afforded 1,3,5-trisubstituted benzenes 7b–d and 8b–d resulting from self-condensation of one enaminone with two molecules of the other enaminone. Heating enaminone 2b with ethyl propiolate afforded a mixture of triaroylbenzene 3b in addition to diaroylbenzoic acid esters 11 and 1,3,5-aroylbenzene dicarboxylate 12. On the other hand, reaction of enaminone derivative 2b with dimethyl acetylenedicarboxylate has afforded 2-oxopyran-4-carboxylic acid derivative 15. 2-Aminoprop-1-ene-1,1,3-tricarbonitrile 16 was reacted with enaminones to yield polysubstituted benzenes 19a–c. Likewise the reaction of 2-aminoprop-1-ene-1,1,3-tricarbonitrile 16 with benzylidenemalononitrile has afforded polysubstituted benzenes 24. |
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Keywords: | 1,3,5-trisubstituted benzenes enaminone 2-aminoprop-1-ene-1,1,3-tricarbonitrile 1,3,5-aroylbenzene dicarboxylate montmorillonite-K-10 |
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