No abstract

A convenient, fast and environmentally benign procedure for the synthesis of a new series of highly functionalized N-alkylated pyridines as privileged medicinal scaffolds was developed via a unique three-component reaction of easily available aromatic as well as heteroaromatic aldehydes, N-alkyl-2-cyanoacetamides and malononitrile in EtOH in the presence of K2CO3 as a base promoter under microwave irradiation. The presented tandem process is presumed to proceed via Knoevenagel condensation, Michael addition, intramolecular cyclization, autoxidation and subsequent aromatization. Particularly valuable features of this protocol, including high product yields, mild conditions, atom-efficiency, simple execution, short reaction times and easy purification make it a highly efficient and promising synthetic strategy to prepare substituted pyridine nuclei. The proposed mechanism of this novel one-pot reaction and structure elucidation of the products are discussed.

Fused tetracyclic systems containing a quinoline nucleus represent an important class of heterocyclic bioactive natural products and pharmaceuticals because of their significant and wide-spectrum biological properties.

An efficient and convenient synthesis of pyrrolidinones and pyridinones utilizing enamino esters as starting material has been described. The structures of the compounds obtained were confirmed by spectral and elemental analyses.

New 1,2,4-triazole colorants were obtained, in high yields, by coupling 3-ethylthio-5-cyanomethyl-4-phenyl-1,2,4-triazole (1) with diazotized aniline derivatives 2, 4 and 6. The azo dyes prepared in this work may exist in three tautomeric forms. We found that the tautomerism is influenced mainly by the nature of substituent at the para position of the aniline coupling component. This tautomerisation was observed in the NMR spectra of the dyes. The dyes were characterized by IR, 1 H-NMR, 13 C-NMR and MS spectroscopic techniques.

2-Pyridylacetonitrile (1) couples with aromatic diazonium salts to yield arylhydrazones 2a-c, that were shown to exist in the syn-form 2 rather than the anti-form 4. Compounds 2a,c reacted with hydroxylamine in refluxing DMF to yield the interesting 1,2,3-triazolylpyridines 6. Attempts to cyclize 2 to give the corresponding fused pyrazolopyridines 9 failed. On the other hand, compound 1 condensed with dimethylformamide dimethyl acetal to yield enaminonitrile 10 that could be converted into pyrazolylpyridine 11.

No abstract

We herein describe the first review which aims to focus soberly the various synthetic methods and chemical reactions of chloroquinoline-3-carbonitrile derivatives. The reactions are subdivided into groups that cover reactions of chloro substituent at 2 or 4 and 2,4 positions, as well as cyano substituent at 3 position and reactions which involve both groups. Most types of reactions have been successfully applied and used in the production of biologically active compounds.