Mekheimer RA, Abdel Hameed AM, Sadek KU. First synthesis and isolation of the E- and Z-isomers of some new Schiff bases. Reactions of 6-azido-5-formyl-2-pyridone with aromatic amines.
Molecules 2008;
13:195-203. [PMID:
18259142 PMCID:
PMC6245304 DOI:
10.3390/molecules13010195]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 02/25/2007] [Indexed: 11/16/2022] Open
Abstract
Some novel Schiff bases have been prepared by reacting 6-azido-5-formyl-2-pyridone 1 with a series of aromatic amines 2a-f. 5-Arylaminomethylene-6-(E)-aryl-iminopyridones 3a-e were obtained by reaction of 1 with 2a-e at room temperature, whereas with 2f, the 6-azido-5-naphthalen-2-yl-iminomethylpyridone derivative 4 was formed. On the other hand, heating 1 with 2a-d at 140-150 degrees C yielded two sets of isomeric products, (E)-3a-d and (Z)-5a-d. Refluxing compounds (Z)-3a,c with hydroxyl-amine in methanol gave the corresponding hydroxyliminopyridones 8a,c. Heating of (E)-3a-d with excess POCl3 at reflux did not give the expected tricyclic compound 9, but rather the isomeric products (Z)-5a-d were obtained. The structures of all these products have been characterized using IR and 1H- and 13C-NMR spectroscopy.
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