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Molecules 2018, 23(11), 2925; https://doi.org/10.3390/molecules23112925

Quinazolin-4(3H)-ones and 5,6-Dihydropyrimidin-4(3H)-ones from β-Aminoamides and Orthoesters

Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA
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Received: 28 October 2018 / Accepted: 8 November 2018 / Published: 9 November 2018
(This article belongs to the Collection Heterocyclic Compounds)
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Abstract

Quinazolin-4(3H)-ones have been prepared in one step from 2-aminobenzamides and orthoesters in the presence of acetic acid. Simple 2-aminobenzamides were easily converted to the heterocycles by refluxing in absolute ethanol with 1.5 equivalents of the orthoester and 2 equivalents of acetic acid for 12–24 h. Ring-substituted and hindered 2-aminobenzamides as well as cases incorporating an additional basic nitrogen required pressure tube conditions with 3 equivalents each of the orthoester and acetic acid in ethanol at 110 °C for 12–72 h. The reaction was tolerant towards functionality on the benzamide and a range of structures was accessible. Workup involved removal of the solvent under vacuum and either recrystallization from ethanol or trituration with ether-pentane. Several 5,6-dihydropyrimidin-4(3H)-ones were also prepared from 3-amino-2,2-dimethylpropionamide. All products were characterized by melting point, FT-IR, 1H-NMR, 13C-NMR, and HRMS. View Full-Text
Keywords: quinazolin-4(3H)-ones; 5,6-dihydropyrimidin-4(3H)-ones; heterocycle synthesis; 2-aminobenzamides; orthoesters quinazolin-4(3H)-ones; 5,6-dihydropyrimidin-4(3H)-ones; heterocycle synthesis; 2-aminobenzamides; orthoesters
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Gavin, J.T.; Annor-Gyamfi, J.K.; Bunce, R.A. Quinazolin-4(3H)-ones and 5,6-Dihydropyrimidin-4(3H)-ones from β-Aminoamides and Orthoesters. Molecules 2018, 23, 2925.

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