K. Daoud, A. Ahmad, A. Ali
Sep 1, 2009
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0
Influential Citations
2
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Journal
Journal of Education Science
Abstract
In this paper the synthesis of some 2-(3-pyridyl)-5-aryl-1,3,4oxadiazoles from hydrazones is reported. Nicotinic acid was converted to ethyl nicotinate (1) by its reaction with thionyl chloride and the resultant acid chloride was treated with absolute ethanol, the ethyl nicotinates was treated with hydrazine hydrate in ethanol to give the corresponding acid hydrazide (2). The acid hydrazide was treated with benzaldehyde or substituted benzaldehyde to give the hydrazones (3-8). The hydrazones were cyclized to 2-(3-pyridyl)-5-aryl-1,3,4-oxadiazoles (4-14) by their reaction with lead oxide. The structure of the synthesised compounds were confirmed by physical and spectral methods. Synthesis of Some Substituted 1,3,4-Oxadiazoles from Hydrazones. 21 ITRODUCTION Substituted 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazoles were known to posses various biological activities and other uses. 2-[3Chloro-5-(trifluromethyl)-2-pyridyloxy methyl]-5-aryl-1,3,4-oxadiazoles(1) was show activity against Leucana separate walkan, while 5-(1adimental)-1,3,4-oxadiaxole-2-thione show antivirus activities. Compound (2) show broad spectrum of antiinflammatory activity. In industrial field 2,5-Bis(4-dimethylamino phenyl)-1,3,4oxadiazole act as corrosion inhibitors (4) . The synthesis of 1,3,-oxadiazoles were achieved from hydrazide by its reaction with carbon disulfide in pyridine (5) or ethanolic potassium hydroxide (6) . Compound (3) was synthesized from the reaction hydrazide with carbon disulfide in ethanolic potassium hydroxide (7) . The oxidation of substituted thiosemicarbazides with various reagents such as lead oxide (8) , mercuric acetate (9) and iodine/potassium iodine (10) afforded substituted 1,3,4-oxadiazoles. The hydrazides were converted to substituted 1,3,4-oxadiazoles by their reaction with carboxylic acid in presence of phosphorus oxychloride (11) . Substituted 1,3,4-oxadiazole were synthesized by many research workers due to their biological importance such as antibacterial (12) , anticancer (13) as compound (4), and anti-inflammatory (14) . N F3C Cl