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)
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-TextKeywords:
quinazolin-4(3H)-ones; 5,6-dihydropyrimidin-4(3H)-ones; heterocycle synthesis; 2-aminobenzamides; orthoesters
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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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