Chemistry and application of 4-oxo-4H-1-benzopyran-3-carboxaldehyde
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.
About: This article is published in Journal of Heterocyclic Chemistry.The article was published on 2008-11-01. It has received 42 citations till now. The article focuses on the topics: Benzopyran.
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71 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: The first synthesis of 3-methoxalylchromone was described, where the reaction of the latter with electron-rich aminoheterocycles afforded a set of heteroannelated pyridines bearing a CO(2)Me substituent located at the α-position of the pyridine core.
Abstract: The first synthesis of 3-methoxalylchromone was described. The reaction of the latter with electron-rich aminoheterocycles afforded a set of heteroannelated pyridines bearing a CO2Me substituent located at the α-position of the pyridine core.
34 citations
TL;DR: This review will cover the literature on the chromone and pyrazole dual chemistry and their outcomes in the 21st century with a focus on the synthesis of chromone-pyrazole dyads.
Abstract: Chromones, six-membered oxygen heterocycles, and pyrazoles, five-membered two-adjacent-nitrogen-containing heterocycles, represent two important classes of biologically active compounds. Certain derivatives of these scaffolds play an important role in medicinal chemistry and have been extensively used as versatile building blocks in organic synthesis. In this context, we will discuss the most relevant advances on the chemistry that involves both chromone and pyrazole rings. The methods reviewed include the synthesis of chromone-pyrazole dyads, synthesis of chromone-pyrazole-fused compounds, and chromones as starting materials in the synthesis of 3(5)-(2-hydroxyaryl)pyrazoles, among others. This review will cover the literature on the chromone and pyrazole dual chemistry and their outcomes in the 21st century.
33 citations
Cites background from "Chemistry and application of 4-oxo-..."
...The reactivity of 3-formylchromone derivatives with a series of hydrazines has been studied in detail over the most recent years (for recent reviews see [103,104])....
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References
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14 citations
TL;DR: In this article, a new 7,16-bis (quinolin-8-ylmethyl)-1,4,10,13-tetraoxa-7,16diazacyclooctadecane ligand, L, has been prepared and its crystal structure reported.
14 citations
TL;DR: In contrast to coumarin chemistry, there is no ring expansion into the 1-benzoxepin series as mentioned in this paper, and therefore no corresponding shift (and therefore no ringexpansion) for any 3-acylchromone adduct.
Abstract: In general, chromones activated by electron-withdrawing groups at position 3 are alkylated (at position 2) by diazoalkanes in the same manner as the isomeric coumarins. For example, 6-methylchromone-3-carbonitrile (3a) is converted by diazoethane into 2-ethyl-6-methylchromone-3-carbonitrile (3c). 2-Diazopropane affords cyclopropane by-products as well, and a 3-formyl group usually suffers homologation to the appropriate ketone, as when 2-diazopropane converts 3-formyl-6-methylchromone into 2-isopropyl-6-methyl-3-(methylpropanoyl)chromone (8). In marked contrast to coumarin chemistry, there is no ring expansion into the 1-benzoxepin series.Chromones activated at position 2 show diverse reactions. Although nitriles are usually considered to be unreactive towards diazoalkanes, 6-methylchromone-2-carbonitrile slowly gives a triazole; subsequent protropy and further alkylation results in the isolation of what is provisionally considered to be the 2-(1,2,3-triazol-4-yl)chromone (12a). 2-Formylchromone (13a) is converted by diazomethane into a mixture of 2-acetylchromone and the 2-oxiranylchromone (14) but it does undergo ring expansion by diazoethane and 2-diazopropane giving derivatives of 1-benzoxepin, e.g. (15). Ethyl chromone-2-carboxylate (17a) reacts very slowly but affords 1-benzoxepin derivatives as well as 3-alkylated chromones.The ring-expansions are considered to occur by way of sigmatropic shifts in unstable pyrazolines as in diagram (20) for a 2-acylchromone adduct. There is no corresponding shift (and therefore no ring-expansion) for any 3-acylchromone adduct [diagram (6a)] whence it appears that sigmatropic shifts of oxygen are unexpectedly difficult.
14 citations
TL;DR: In this paper, the properties of monomeric and polymeric binuclear complexes of Schiff bases derived from 6-formylkhellin and aromatic diamines with cobalt(II), nickel(II) and copper(II).
13 citations
12 citations