Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products.
TL;DR: A survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc.
Abstract: This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the γ-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.
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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: In this article, the starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride.
38 citations
TL;DR: A new mode of three-component reactions between isocyanoacetates, amines and 3-formylchromones is presented, which enables an efficient synthesis of polysubstituted pyrroles.
36 citations
TL;DR: In this paper, a simple and convenient synthesis of pyrido[1,2-a ]benzimidazoles was efficiently achieved from the condensation reactions of 1 H -benzimaidazol-2-ylacetonitrile (1 ) with some 3-substituted chromones, chromone-3-carboxylic acids and chromone -carboxamides.
34 citations
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TL;DR: In this paper, the principles underlying the dielectric heating effects observed for chemical compounds in solution and in the solid state are presented, and applications of the technique to a wide range of chemical syntheses have also been indicated.
Abstract: This review has presented the principles underlying the dielectric heating effects observed for chemical compounds in solution and in the solid state. The applications of the technique to a wide range of chemical syntheses have also been indicated. The field is in its infancy and therefore much of the effort to date has been directed towards understanding the rate enhancements of known reactions. The next few years should see the isolation of new compounds using microwave heating techniques
1,067 citations
TL;DR: In this paper, the authors present a review of applications of microwave energy in ORGANIC CHEMISTRY, focusing on the application of MICROWAVE ENERGY in organic preparation and procedures.
380 citations
TL;DR: In this article, microwave irradiation using commercial domestic ovens is very efficient to activate potassium acetate on alumina in the absence of solvent (dry media) giving rise to remarkable rate enhancements in alkylation reactions with long chain halides.
121 citations
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
104 citations