ChemInform Abstract: Synthesis and Chemical Reactivity of 2‐Methylchromones

Ibrahim, Magdy A.; Ali, Tarik E.; Alnamer, Youssef A.; Gabr, Yassin

doi:10.1002/chin.201023250

Cited by 6 publications

(7 citation statements)

References 1 publication

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“…This strategy was applied to the 2-methylchromone derivative 2b, however, the demethylation step led to the undesired cleavage of both methyl groups (2 0 -OMe and 7-OMe). The analysis of the 1 H NMR spectrum of the crude product of the reaction with boron tribromide showed the presence of two singlets corresponding to protons 2 0 -OH and 7-OH, as well as another singlet corresponding to 7-OCH 3 . The existence of a 7-OH group of the chromone moiety creates another undesired propargylation site, avoiding the selective propargylation of 2 0 -OH.…”

Section: Synthesis Of the Starting Chromonesmentioning

confidence: 99%

“…1,2 This ring system is also a useful substrate for further functionalization, which can be achieved through oxidation, condensation, conjugate addition or Diels-Alder (DA) reactions. 3,4 In fact, a DA reaction is one of the most powerful cycloaddition reactions in organic synthesis and particularly, in the construction of 6-membered rings, combining dienes and dienophiles with different substitution patterns. 5,6 There are countless examples of natural products and other complex structures synthesized through this approach, with an outstanding degree of control and a high level of predictability for this process.…”

Section: Introductionmentioning

confidence: 99%

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First intramolecular Diels–Alder reactions using chromone derivatives: synthesis of chromeno[3,4-b]xanthones and 2-(benzo[c]chromenyl)chromones

et al. 2018

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A series of novel (E)-2-(2-propargyloxystyryl)chromones and (E,E)-2-[4-(2-propargyloxyphenyl)buta-1,3-dien-1-yl]chromones were designed and synthesized via aldol condensation of 2-methylchromones with 2-propargyloxy(benzaldehyde and cinnamaldehyde), respectively. Both chromone derivatives were used as substrates in microwave-assisted intramolecular Diels-Alder reactions, affording chromeno[3,4-b]-xanthones and 2-(benzo[c]chromenyl)chromones. This is the first report involving chromone derivatives in intramolecular Diels-Alder reactions for the synthesis of new oxygen heterocycles, namely xanthoneand flavone-type compounds.

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Section: Synthesis Of the Starting Chromonesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

First intramolecular Diels–Alder reactions using chromone derivatives: synthesis of chromeno[3,4-b]xanthones and 2-(benzo[c]chromenyl)chromones

et al. 2018

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“…The reactivity of 2-methyl-4H-chromen-4-ones has been the main topic of several works [18]. Among them, there are a number of condensation reactions with carbonyl compounds to afford new heterocyclic systems.…”

Section: Chemistrymentioning

confidence: 99%

Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities

Proença

Albuquerque

Ribeiro

et al. 2016

European Journal of Medicinal Chemistry

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a b s t r a c tChromones and xanthones are oxygen-containing heterocyclic compounds acknowledged by their antioxidant properties. In an effort to develop novel agents with improved activity, a series of compounds belonging to these chemical classes were prepared. Their syntheses involve the condensation of appropriate 2-methyl-4H-chromen-4-ones, obtained via Baker-Venkataraman rearrangement, with (E)-3-(3,4-dimethoxyphenyl)acrylaldehyde to provide the corresponding 2-[(1E,3E)-4-(3,4-dimethoxyphenyl)buta-1,3-dien-1-yl]-4H-chromen-4-ones. Subsequent electrocyclization and oxidation of these compounds led to the synthesis of 1-aryl-9H-xanthen-9-ones. After cleavage of the protecting groups, hydroxylated chromones and xanthones were assessed as scavenging agents against both reactive oxygen species (ROS) [superoxide radical (O 2 -), hydrogen peroxide (H 2 O 2 ), hypochlorous acid (HOCl), singlet oxygen ( 1 O 2 ), and peroxyl radical (ROO )] and reactive nitrogen species (RNS) [nitric oxide ( NO) and peroxynitrite anion (ONOO À )]. Generally, all the tested new hydroxylated chromones and xanthones exhibited scavenger effects dependent on the concentration, with IC 50 values found in the micromolar range. Some of them were shown to have improved scavenging activity when compared with previously reported analogues, allowing the inference of preliminary conclusions on the structure eactivity relationship.

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“…Chromones are naturally occurring oxygen‐containing heterocyclic compounds that perform important biological functions in nature . Although 2‐methylchromones 1 constitute a small family of naturally occurring compounds, their synthesis and transformations into other biologically active compounds have been exploited . It is known that the pyrone ring of 1 is susceptible to ring opening under the action of N ‐nucleophiles such as amines , hydrazines , hydroxylamine , and thiourea .…”

Section: Introductionmentioning

confidence: 99%

Reactions of 2‐Methylchromones with Cyanoacetamides and Ethyl Cyanoacetate. Synthesis of 6‐(2‐Hydroxyaryl)‐4‐methyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitriles and 7‐Hydroxy‐6‐imino‐9‐methyl‐6H‐benzo[c]chromene‐8‐carbonitriles

Sosnovskikh¹,

Anufriev²,

Safrygin³

et al. 2013

Journal of Heterocyclic Chem

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Although 2‐methylchromones react with cyanoacetamide and N‐methyl cyanoacetamide in the presence of sodium ethoxide in refluxing ethanol to produce 6‐(2‐hydroxyaryl)‐4‐methyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitriles, their reactions with ethyl cyanoacetate under the same conditions took an entirely different course and gave 7‐hydroxy‐6‐imino‐9‐methyl‐6H‐benzo[c]chromene‐8‐carbonitriles.

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ChemInform Abstract: Synthesis and Chemical Reactivity of 2‐Methylchromones

Cited by 6 publications

References 1 publication

First intramolecular Diels–Alder reactions using chromone derivatives: synthesis of chromeno[3,4-b]xanthones and 2-(benzo[c]chromenyl)chromones

First intramolecular Diels–Alder reactions using chromone derivatives: synthesis of chromeno[3,4-b]xanthones and 2-(benzo[c]chromenyl)chromones

Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities

Reactions of 2‐Methylchromones with Cyanoacetamides and Ethyl Cyanoacetate. Synthesis of 6‐(2‐Hydroxyaryl)‐4‐methyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitriles and 7‐Hydroxy‐6‐imino‐9‐methyl‐6H‐benzo[c]chromene‐8‐carbonitriles

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