Chemistry of 4-Oxo-4H-1-benzopyran-3-carbonitrile
TL;DR: The 3-cyanochromone 3-oxide 4-oxo-4H1-benzopyran-3-yl moiety is referred to as Chr-X as discussed by the authors.
About: This article is published in Journal of Heterocyclic Chemistry.The article was published on 2005-09-01. It has received 31 citations till now. The article focuses on the topics: Nitrile & Cycloaddition.
Citations
More filters
TL;DR: In this article, the pyrone ring of 3-polyfluoroacyl-4 H -chromeno[3,4- d ]isoxazol-4-ols was opened by nucleophilic 1, 4-addition and subsequent cyclization to 4 polyfluoroalkyl)-4 H-chromeno, which was then converted to 3-R F -4-salicyloylisoxazoles by simple heating.
45 citations
TL;DR: In this paper, a proof of structures and a probable reaction pathway for 3-substituted chromones with hydroxylamine in alkaline medium were presented, and a possible reaction pathway was presented for 3-(diaminomethylene)chroman-2,4-dione.
43 citations
TL;DR: The chemistry and application of the title aldehyde and some simple derivatives thereof are reviewed in this paper, where the authors propose a simple derivative of the aldehydes, which they call simple aldeheeds.
42 citations
TL;DR: Another aspect concerning chromone chemistry leading to the one-pot synthesis of functionalized novel spirobenzofuranones has been described, and a plausible mechanistic rationale is proposed.
Abstract: Another aspect concerning chromone chemistry leading to the one-pot synthesis of functionalized novel spirobenzofuranones has been described. The synthesis involves reaction of the zwitterionic intermediates formed by the 1:1 interaction between isocyanides and acetylenecarboxylates with 3-cyanochromones, whereupon through an unexpected and unprecedented reaction of the chromone moiety the isolated benzofuranones are formed. The regioselectivity of the reaction was investigated by DFT calculations. The geometries of the intermediates, transition structures, and intermediate products, leading to the final products, were optimized using the B3LYP functional with the 6-31G(d) basis set. The structures of the products were elucidated by 1D and 2D NMR experiments. Full assignment of all (1)H and (13)C NMR chemical shifts has been achieved. A plausible mechanistic rationale is proposed.
35 citations
TL;DR: The structure elucidation of the products was accomplished by 1D and 2D NMR experiments and confirmed by X-ray crystallographic analysis, and full assignment of all (1)H and (13)C NMR chemical shifts has been unambiguously achieved with the aid of DFT/GIAO calculations.
Abstract: The reaction of the zwitterionic intermediate, generated in situ from either tert-butylisocyanide or cyclohexylisocyanide and acetylenedicarboxylates, with 3-cyanochromones is described, whereupon spirochromenofuran derivatives 5 or 6 were obtained in good yields. The subsequent acid-catalyzed rearrangement of the isolated 2-imino-spirochromenofurans 5 to 2-amino-spirochromenofurans 7 has also been studied. Rational mechanistic schemes for the formation of compounds 5, 6, and 7 are proposed. The structure elucidation of the products was accomplished by 1D and 2D NMR experiments and confirmed by X-ray crystallographic analysis. Full assignment of all 1H and 13C NMR chemical shifts has been unambiguously achieved with the aid of DFT/GIAO calculations.
29 citations
References
More filters
TL;DR: A number of 3-(1H-tetrazol-5-yl)chromones were synthesized and found to have antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) test and are of possible value for the treatment of asthma.
Abstract: A number of 3-(1H-tetrazol-5-yl)chromones were synthesized and found to have antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) test. These compounds are active when administered orally in rats and of possible value for the treatment of asthma.
117 citations
TL;DR: Compounds bearing an alkyl group, especially an isopropyl group at the 7-position, were superior in activity to the corresponding unsubstituted compounds.
Abstract: 5-Oxo-5H-[1]benzopyrano[2,3-b]pyridine-3-carboxylic acids 23 and their tetrazole analogues 24 were synthesized from 4-oxo-4H-1-benzopyran-3-carbonitriles 3 or 2-amino-4-oxo-4H-1-benzopyran-3-carboxaldehydes 4. When administered intravenously, they exhibited antiallergic activity in a reaginic PCA test in rats. In the carboxylic acid series, the activity was influenced by the substituents at the 2-position and increased substantially in the following order: Me, OMe less than NH2 less than OH, H less than NHOMe. On the other hand, in the tetrazole series, 2-unsubstituted derivatives showed the highest activity. Regardless of the kinds of substituents at positions 2 and 3, compounds bearing an alkyl group, especially an isopropyl group at the 7-position, were superior in activity to the corresponding unsubstituted compounds. Among these alkyl derivatives, 3-carboxylic acid derivatives, i.e., 23c (7-ethyl), 23g (2-amino-7-isopropyl), 23r [2-(methoxyamino)-7-isopropyl], and a 3-tetrazole derivative 24c (7-isopropyl), were 41-184 times as potent as disodium cromoglycate. They also exhibited remarkable activity when administered orally; clinical studies on 23g (AA-673) are in progress.
87 citations
TL;DR: The metabolites and degradation products of 2-amino-7-isopropyl-5-oxo-5H-[1] benzopyrano-[2, 3-b] pyridine-3-carboxylic acid were synthesized to confirm the proposed structures and to determine their activity in the rat passive cutaneous anaphylaxis test.
Abstract: The metabolites and degradation products of 2-amino-7-isopropyl-5-oxo-5H-[1] benzopyrano-[2, 3-b] pyridine-3-carboxylic acid (Amoxanox, AA-673, 1), a promising drug for the treatment of bronchial asthma, were synthesized to confirm the proposed structures and to determine their activity in the rat passive cutaneous anaphylaxis test.
85 citations
TL;DR: In this article, a novel synthesis of 3-(hydroxymethyl)chromones from o-hydroxy-ω-(methylsulfinyl)acetophenones has been developed.
58 citations