Microwave-Assisted,Multicomponent, Ecofriendly Synthesis of 3-Bihetaryl-2-oxindole Derivatives Grafted with Phenothiazine Moiety |
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Authors: | A S Al-Bogami A S El-Ahl |
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Institution: | 1. Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabiaelahl2002@yahoo.com;3. Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia;4. Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt |
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Abstract: | A series of 3-(3′-pyrrolyl)-2-oxindoles incorporating the phenothiazine moiety has been synthesized under both conventional and microwave heating conditions via multicomponent reaction of 3-(2-(phenothiazin-2-yl)-2-oxoethylidene)-2-oxindole derivatives, acyclic and cyclic 1,3-dicarbonyl compounds, and ammonium acetate. The resulting 2-oxindole derivatives underwent selective chloroacetylation at both the oxindole and the phenothiazine NH groups. Treatment of the dichloroacetylated compound with 2 mol of sodium azide in acetone under reflux gave the corresponding monoazide with concomitant dechloroacetylation of the N-chloroacetyl group of the oxindole ring. Huisgen 1,3-dipolar cycloaddition of the resulted alkyl azide with diethyl acetylene–dicarboxylate afforded the corresponding triazole derivative in good yield. Furthermore, the dichloroacetylated compound could be easily cyclized into 4-(3-oxo-2,3-dihydroxazolo3,2-a]indol-9-yl)-1H-pyrrole-3-carboxylate derivative by treatment with sodium hydride in dry toluene. The yields and rate of reactions significantly improved under microwave heating conditions. |
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Keywords: | 2 3-Dihydroxazolo[3 2-a]indole Michael addition microwave phenothiazine 3-(3′-pyrrolyl)-2-oxindole triazole |
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