Reaction of 3-arylidenepropenoic acid derivatives with triethylamine and other amines; unexpected reductions and vinylogations

Harisha, Attimogae Shivamurthy and Nayak, Suresh Parameshwar and Nagarajan, Kuppuswamy and Row, Tayur Narasingarow Guru and Hosamani, Amar A (2016) Reaction of 3-arylidenepropenoic acid derivatives with triethylamine and other amines; unexpected reductions and vinylogations. In: TETRAHEDRON, 72 (22). pp. 2880-2889.

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Abstract

Exposure of ethyl 2-cyano-3-(2-methoxy-5-nitrophenyl)acrylate if to triethylamine in hot ethanol resulted in the formation of the dihydro derivative 2f and vinylogue 3f in high yields. Single crystal X-ray data are provided for 3f. Similar reactions were observed for various analogues. The reaction was studied changing aryl substituent, amines and solvents. Pyridyl, thienyl analogues were also examined. The study was extended to cyclic molecules incorporating such systems like thiazolidinedione 8, 3-cyanocoumarin 9 and 4-arylidene-isoquinoline-2,4-diones 11. The last group gave vinylogated products, 4-cinnamylidene-isoquinolinediones and 4-hydroxylated species. A few examples of arylidene derivatives from malononitrile, ethyl acetoacetate, acetyl acetone and ethyl methylsufonylacetate were investigated. Ethyl cinnamate and beta-nitrostyrene were unaffected. The reaction is considered to be possibly radical mediated, since addition of free radical quencher suppressed the reaction. Contrary to the effects of thermal conditions, irradiation of If in ethanol at 254 and 365 nm gave complex mixtures. A few other interesting observations in this study are noted: vinylogation of If with acetaldehyde to 3f; formation of 3f from if by the treatment with triethylamine, palladium carbon and reduction of if to 2f by triethylammonium formate in DMF. (C) 2016 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	TETRAHEDRON
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Keywords:	3-Aryl-2-cyanoprop-2-enoates; Triethylamine; Reduction; Vinylogation
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	30 Jun 2016 04:48
Last Modified:	30 Jun 2016 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/54082

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