A novel route for the preparation of chromenoquinazolines
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It is known that multicomponent reactions involving three or more reagents reacting successively to form a novel product containing the basic structural components of all of the starting molecules are a promising approach for the preparation of heterocyclic compounds. One such method is the Biginelli reaction [1, 2, 3, 4, 5].
In this study, 3-(1,3-dioxobutan-1-yl)-2H-chromen-2-one (1), aromatic aldehydes 2a,b, and urea (3) have been used in the Biginelli reaction for the first time. The reaction has been carried out, again for the first time, in both the classical one-pot variation via refluxing in ethanol in the presence of hydrochloric acid, and also solvent-free by 700 Watt microwave irradiation and zinc chloride catalyst.
It was found that the nature of the substituent in the aromatic component did not affect the direction of transformation and the yield of the novel, linearly structured condensed systems, namely, 11a-hydroxy4-phenyl- (4) and...
Keywords2H-chromen-2-one chromenoquinazoline microwave irradiation Biginelli reaction
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