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Open AccessArticle

A Simple Precursor for Highly Functionalized Fused Imidazo[4,5-b]pyridines and Imidazo[4,5-b]-1,8-naphthyridine

1
Chemistry Department, College of Science, IMSIU (Al-Imam Mohammad Ibn Saud Islamic University), Riyadh 11623, Saudi Arabia
2
Photochemistry Department, National Research Centre, Cairo 12622, Egypt
*
Authors to whom correspondence should be addressed.
Academic Editor: Derek J. McPhee
Molecules 2016, 21(12), 1646; https://doi.org/10.3390/molecules21121646
Received: 23 September 2016 / Revised: 21 November 2016 / Accepted: 23 November 2016 / Published: 1 December 2016
(This article belongs to the Section Organic Chemistry)
1-alkyl aryl-5-amino-4-(cyanoformimidoyl)imidazoles 4 were reacted with malononitrile and 2-amino-1,1,3-propenetricarbonitrile under mild experimental conditions, which led to 5-amino-3-(substituted benzyl)-6,7-dicyano-3H-imidazo[4,5-b]pyridines 5 and 6,8-diamino-3-(4-substituted benzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7,9-dicarbonitrile 6, respectively, when the reaction was carried out in the absence of a base, or to 5,7-diamino-3-(4-alkyl aryl)-3H-imidazo[4,5-b]pyridine-6-carbonitrile 8, and 6,8,9-triamino-3-(4-substitutedbenzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7-carbonitrile 10 in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU). Both reactions evolved from an adduct formed by nucleophilic attack of the malononitrile anion or 2-amino-1,1,3-propenetricarbonitrile anion to the carbon of the cyanoformimidoyl substituent. In the case of the malononitrile anion, a 5-amino-1-alkyl aryl-4-(1-amino-2,2-dicyanovinyl)imidazole 7 was isolated when this reaction was carried out in the presence of DBU. The structure of compound 7 was confirmed by spectroscopic methods, and cyclized intramolecularly to 8 by heating in ethanol/triethyl amine. View Full-Text
Keywords: imidazo[4,5-b]pyridine; diaminomaleonitrile; carbon acid; imidazo[4,5-b]-1,8-naphthyridine; malomonitrile; 2-amino-1,1,3-propenetricarbonitrile imidazo[4,5-b]pyridine; diaminomaleonitrile; carbon acid; imidazo[4,5-b]-1,8-naphthyridine; malomonitrile; 2-amino-1,1,3-propenetricarbonitrile
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MDPI and ACS Style

Al-duaij, O.K.; Zaki, M.E.; El Gazzar, A.-R.B.A. A Simple Precursor for Highly Functionalized Fused Imidazo[4,5-b]pyridines and Imidazo[4,5-b]-1,8-naphthyridine. Molecules 2016, 21, 1646.

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