oa South African Journal of Chemistry - Synthesis of new benzocoumaryl oxadiazolyls as strong blue-green fluorescent brighteners : research article
|Article Title||Synthesis of new benzocoumaryl oxadiazolyls as strong blue-green fluorescent brighteners : research article|
|© Publisher:||South African Chemical Institute (SACI)|
|Journal||South African Journal of Chemistry|
|Affiliations||1 Kuvempu University, India, 2 Kuvempu University, India, 3 Kuvempu University, India and 4 Kuvempu University, India|
|Publication Date||Jan 2011|
|Pages||88 - 94|
|Keyword(s)||Benzocoumarin-3-ethylcarboxylate, Benzocoumaryl oxadiazolyls and Fluorescent brighteners|
The benzocoumarin-3-ethylcarboxylate 2 on treatment with hydrazine hydrate at room temperature afforded benzocoumarin-3-carbohydrazide 3. The compound 3 served as key intermediate in the synthesis of the title compounds. Thus, benzocoumarin-1,3,4-oxadiazolyls 6a-e were obtained in two ways, i.e. one by direct cyclization of benzocoumarin-3-carbohydrazide 3 with substituted benzoic acids in POCl3 and the other by cyclization of Schiff bases of compounds 5a-e in the presence of bromine/acetic acid. The structures of the novel benzocoumaryl oxadiazolyls 6a-e were confirmed by spectral analysis. The benzocoumarin-1,3,4-oxadiazolyls 6a-e exhibited strong blue and green fluorescent properties. The Stoke's shifts range from 43 to 165 nm. The absorption and fluorescence maxima of the benzocoumaryl oxadiazolyls showed good bathochromic shifts.
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