title: Synthesis of (E)-2-Styrylchromones and Flavones by Base-Catalyzed Cyclodehydration of the Appropriate β-Diketones Using Water as Solvent.
abstract: A low cost, safe, clean and environmentally benign base-catalyzed cyclodehydration of appropriate β-diketones affording (E)-2-styrylchromones and flavones in good yields is disclosed. Water was used as solvent and the reactions were heated using classical and microwave heating methods, under open and closed vessel conditions. β-Diketones having electron-donating and withdrawing substituents were used to evaluate the reaction scope. The reaction products were isolated in high purity by simple filtration and recrystallization from ethanol, when using 800 mg of the starting diketone under classical reflux heating conditions.
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal. jfpinto@ua.pt.
authors.forename: Joana
authors.initials: J
authors.lastname: Pinto
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal. verasilva@ua.pt.
authors.forename: Vera L M
authors.initials: VL
authors.lastname: Silva
authors.affiliation: UCIBIO/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal. ana.silva@fc.up.pt.
authors.forename: Ana M G
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal. artur.silva@ua.pt.
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
mesh_terms: D000468:Alkalies / Q000737:chemistry; D002384:Catalysis; D002867:Chromones / Q000138:chemical synthesis* / Q000737:chemistry; D047309:Flavones / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000468:Alkalies; D002867:Chromones; D047309:Flavones; D007659:Ketones; D012997:Solvents; D014867:Water
keywords: (E)-2-styrylchromones; cyclodehydration reactions; flavones; microwave heating; reactions in water