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Novel, highly functionalized furan-based polyphenolics were prepared. The employed methodology involves a one-pot 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalyzed 1,4-conjugate addition of 1,3-dicarbonyl compounds on 3-bromochromones, furan heterocyclization, and chromanone ring opening. [ABSTRACT FROM AUTHOR]

The synthesis of ( E )-2-aryl-1-methyl-3-styrylquinolin-4(1 H )-ones, through the Heck reaction of 2-aryl-3-iodo-1-methyl-quinolin-4(1 H )-ones with styrene is described. 2-Aryl-3-iodo-1-methyl-2-quinolin-4(1 H )-ones can be obtained efficiently in a two-step transformation, methylation followed by in situ cyclization of N -(2-acetylphenyl)benzamides into 2-aryl-1-methylquinolin-4(1 H )-ones, which underwent selective 3-iodination with iodine and a catalytic amount of Can. Cyclisation studies of ( E )-2-aryl-1-methyl-3-styrylquinolin-4(1 H )-ones under high temperature or photoinduced electrocyclisation lead to 4-aryl-2-phenylfuro[3,2- c ]quinolines and 12-methyl-5-phenylbenzo[ c ]acridin-7(12 H )-ones. [ABSTRACT FROM AUTHOR]

A facile and rapid access to bridgehead oxygen- and nitrogen-containing spiro bisheterocycles is reported. It involves a one-pot spiro-to-spiro ring transformation of the key spiro[chromanone-hydantoin] compounds into new substituted spiro [hydantoin-diazole], spiro [hydantoin-isoxazole], spiro [hydantoin-diazepine], spiro [hydantoinoxazepine], and spiro [hydantoin-benzodiazepine] upon reaction with appropriate bisnucleophilic agents. The hydantoin cycle is preserved during these chemical reactions affording the spiro bisheterocycles in optimal yields (42-71%). This relevant spiro-to-spiro ring transformation was confirmed by NMR and single-crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

New syntheses of acridin-9(10H)-ones were developed. One involves a two-step transformation, namely the Diels-Alder reactions of (E)-1-methyl-2-styrylquinolin-4(1H)-ones with N-methylmaleimide in refluxing toluene, followed by oxidation of the formed adducts. The second consists in an one-pot procedure using 1,2,4-trichlorobenzene as solvent at 180 °C. The effect of microwave irradition and Lewis acid catalysts in these cycloaddition reactions was also investigated. [ABSTRACT FROM AUTHOR]

A new synthetic route to 5-arylbenzo[c]xanthones is established. This was accomplished by use the Heck reaction of 3-bromoflavones with styrene derivatives, leading to (E)-3-styrylflavones with total diastereoselectivity. This transformation was greatly improved under microwave irradiation. The one-pot, photoinduced electrocyclisation of (E)-3-styrylflavones and further in situ oxidation of the cycloadduct leads to 5-arylbenzo[c]xanthones. [ABSTRACT FROM AUTHOR]

Novel (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro- 1H-xanthene-1,9(2H)-diones are prepared by the cyclization of (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones efficiently catalyzed with boron tribromide. The (E,E)-3-cinnamoyl-5-hydroxy-2- styrylchromones are obtained from the Baker-Venkataraman rearrangement of (E,E)-2-acetyl-1,3-phenylene bis(3-phenylacrylate), which is greatly improved under microwave irradiation. [ABSTRACT FROM AUTHOR]

A novel and efficient route for the synthesis of new benzo[b]acridones has been described. It involves the Diels-Alder reaction of N-substituted-4-quinolone-3-carbaldehyde with ortho-benzoquinodimethanes giving benzo[b]-1,6,6a,12a-tetrahydroacridones, which are the result of a cycloaddition reaction followed by an in situ deformylation. The oxidation of these tetrahydroacridones in dimethyl sulfoxide using a catalytic amount of iodine gives the new benzo[b]acridone derivatives. It was demonstrated that the �cycloaddition reaction is only efficient if an electron-withdrawing N-protecting group is present. [ABSTRACT FROM AUTHOR]

A new synthesis of novel nucleoside analogues is reported. These 5-(2-hydroxybenzoyl)-1,3-disubstituted uracils have been prepared by the coupling of chromone-3-carboxylic acid with carbodiimides, leading to 3-chromone-N-acylureas, which underwent organocatalyzed N-cyclization and chromone ring opening. In the case of ditolylcarbodiimide, the corresponding uracil was obtained by a one-pot, uncatalyzed reaction with chromone-3-carboxylic acid. [ABSTRACT FROM AUTHOR]

A convenient one-pot protocol is developed for the synthesis of 3-methylflavones (III) which are useful precursors for the preparation of (E)-3-styrylflavones (VIII) by Wittig reaction. [ABSTRACT FROM AUTHOR]

The reaction of 3-bromochromones (I) with 1,3-dicarbonyl compounds (II) proceeds via DBU-catalyzed 1,4-conjugate addition, furan cyclization, and chromanone ring opening to afford desired furan-based ortho-phenols (III). [ABSTRACT FROM AUTHOR]