A Green Approach to the Synthesis of Novel Indole Substituted 2-Amino- 4,5-dihydro-3-furancarbonitriles in Water

Author(s): Pannala Padmaja, Pedavenkatagari Narayana Reddy*, Bijaya Ketan Sahoo.

Journal Name: Letters in Organic Chemistry

Volume 16 , Issue 3 , 2019

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Abstract:

2-Amino-4,5-dihydro-3-furancarbonitriles (ADFCs) have attracted much attention due to their utility as valuable synthetic intermediates for the preparation of a series of acyclic and cyclic organic compounds. On the other hand, indoles substituted with furans are highly interesting compounds displaying a wide range of biological and pharmaceutical activities. However, to the best of our knowledge, indole substituted 2-amino-4,5-dihydro-3-furancarbonitriles have not been previously reported. A new and efficient synthesis of indole substituted 2-amino-4,5-dihydro-3-furancarbonitriles has been developed in two steps using water as a solvent. The first step of the sequence involves threecomponent reaction of phenylglyoxals, indoles and malononitrile under aqueous and catalyst-free conditions for the synthesis of indole substituted β,β-dicyanoketones. Reduction of the obtained β,β- dicyanoketones with sodium borohydride in water at room temperature afforded the indole substituted 2-amino-4,5-dihydro-3-furancarbonitriles in good yields. Several substituted phenylglyooxals were reacted smoothly with indole or 2-methylindole and malononitrile to give the corresponding indole substituted β,β-dicyanoketones in good yields. Treatment of the obtained β,β-dicyanoketones with sodium borohydride in water furnished exclusively the indole substituted 2-amino-4,5-dihydro-3- furancarbonitriles in good yields. We have developed an efficient straightforward access to indole substituted β,β-dicyanoketones by one-pot three-component reaction of phenylglyoxals, indoles and malononitrile. The synthetic utility of obtained indole substituted β,β-dicyanoketones has been outlined by the preparation of indole substituted 2-amino-4,5-dihydro-3-furancarbonitriles. The advantage of catalyst-free, atom-economical and environmental benignity render it promising methods for preparation of indole substituted 2-amino-4,5-dihydro-3-furancarbonitriles.

Keywords: 2-Amino-4, 5-dihydro-3-furancarbonitriles, β, β-dicyanoketones, indoles, phenylglyoxals, malononitrile, organic compound.

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Article Details

VOLUME: 16
ISSUE: 3
Year: 2019
Page: [209 - 214]
Pages: 6
DOI: 10.2174/1570178615666180917104820
Price: $58

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