Urea/Thiourea as Ammonia Surrogate: A Catalyst-Free Synthesis of 2-Substituted 2,3-Dihydroquinazolin-4(1H)-ones/Quinazoline-4(3H)-ones |
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| Authors: | P. Paradesi Naidu Akula Raghunadh K. Raghavendra Rao Ramamohan Mekala J. Moses Babu B. R. Rao |
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| Affiliation: | 1. Process Research and Development, Dr. Reddy's Laboratories , Andhra Pradesh , India;2. Organic Research Labs, Department of Organic Chemistry , Andhra University , Visakhapatnam , India;3. Process Research and Development, Dr. Reddy's Laboratories , Andhra Pradesh , India;4. Analytical Research , Custom Pharmaceutical Services, Dr. Reddy's Laboratories , Hyderabad , India |
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| Abstract: | Urea/thiourea have been identified as an effective ammonia surrogate in the construction of quinazolin-4(3H)-one ring. This strategy afforded a simple and catalyst-free synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones via the reaction of isatoic anhydride and aryl aldehydes in the presence of urea or thiourea in ethanol. The reaction proceeded well to afford the quinazolin-4(3H)-one or its dihydro derivative, depending on the nature of carbonyl compounds employed. |
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| Keywords: | Aldehyde isatoic anhydride quinazolin-4(3H)-one urea |
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