NMR and Structural and Conformational Features of 2′-Hydroxychalcones and Flavones

Silva, Artur M. S.; Tavares, Hilário R.; Barros, Ana; Cavaleiro, José A. S.

doi:10.1080/00387019708006750

Cited by 31 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The substrates for biotransformations were obtained by two-step synthesis (Scheme 1). The first step was Claisen-Schmidt condensation between 2 -hydroxy-5 -methylacetophenone (1) and benzaldehyde (2) (purchased from Sigma-Aldrich (St. Louis, MO, USA)) dissolved in methanol, under alkaline conditions at high temperature, according to the method described previously [50][51][52][53]. 2 -Hydroxy-5 -methylchalcone (3) was obtained with a 50.1% yield and was used as the biotransformation substrate, and also as substrate in the second step of the synthesis.…”

Section: Substratesmentioning

confidence: 99%

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

et al. 2020

View full text Add to dashboard Cite

Flavonoids are known for their numerous biological activities; however, their pharmacological application is limited by poor bioavailability. Glycosides are usually more stable and more soluble in water and in this form, flavonoids are present in nature. Likewise, the presence of the methyl group in the flavonoid skeleton results in facilitated absorption and greater bioavailability. Entomopathogenic filamentous fungi are effective in the biotransformation of flavonoids; they are known especially for efficient glycosylation. In the current study we used strains of Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2 to biotransform flavonoids with a single methyl group. 2′-Hydroxy-5′-methylchalcone was biotransformed by both strains into 2′-hydroxy-5′-methylchalcone 3-O-β-D-(4″-O-methyl)-glucopyranoside. In the culture of B. bassiana KCH J1.5 four products were obtained from 6-methylflavanone: 4′-hydroxy-6-methylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside; 4′-hydroxyflavanone 6-methylene-O-β-D-(4″-O-methyl)-glucopyranoside; 6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside and 4′-hydroxy-6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside. Biotransformation with I. fumosorosea KCH J2 as a biocatalyst resulted in the formation of 6-methylflavanone 4′-O-β-D-(4″-O-methyl)-glucopyranoside and 2-phenyl-6-methylchromane 4-O-β-D-(4″-O-methyl)-glucopyranoside. All of these flavonoids can be used in biological activity tests and can be useful in studies concerning structure—bioactivity relationships.

show abstract

Section: Substratesmentioning

confidence: 99%

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The first step was Claisen-Schmidt condensation between 2 ′ -hydroxyacetophenone ( 1 ) and 4-methylbenzaldehyde ( 2 ). The chemical reagents were dissolved in methanol, and the reaction was carried out under alkaline conditions at high temperature 16 – 18 . 2 ′ -Hydroxy-4-methylchalcone ( 3 ) was obtained with 65.5% yield.…”

Section: Resultsmentioning

confidence: 99%

“…4 ′ -Methylflavanone ( 4 ) was received by cyclization of 2 ′ -hydroxy-4-methylchalcone ( 3 ) in the presence of sodium acetate with 37.7% yield. 4 ′ -Methylflavone ( 5 ) was obtained from of 2 ′ -hydroxy-4-methylchalcone ( 3 ) by reaction with iodine excess with 70.0% yield 16 . The data describing obtained synthesis products are shown below and in the Supplementary Materials.…”

Section: Resultsmentioning

confidence: 99%

Interaction of 4′-methylflavonoids with biological membranes, liposomes, and human albumin

Włoch

Strugała

Pruchnik

et al. 2021

Sci Rep

View full text Add to dashboard Cite

The aim of the study was to compare the impact of three synthesized chemical compounds from a group of methylated flavonoids, i.e. 2′-hydroxy-4-methylchalcone (3), 4′-methylflavanone (4), and 4′-methylflavone (5), on a red blood cell membranes (RBCMs), phosphatidylcholine model membranes (PC), and human serum albumin (HSA) in order to investigate their structure–activity relationships. In the first stage of the study, it was proved that all of the compounds tested do not cause hemolysis of red blood cells and, therefore, do not have a toxic effect. In biophysical studies, it was shown that flavonoids have an impact on the hydrophilic and hydrophobic regions of membranes (both RBCMs and PC) causing an increase in packing order of lipid heads and a decrease in fluidity, respectively. Whereas, on the one hand, the magnitude of these changes depends on the type of the compound tested, on the other hand, it also depends on the type of membrane. 4′-Methylflavanone and 4′-methylflavone are located mainly in the hydrophilic part of lipid membranes, while 2′-hydroxy-4-methylchalcone has a greater impact on the hydrophobic area. A fluorescence quenching study proved that compounds (3), (4) and (5) bind with HSA in a process of static quenching. The binding process is spontaneous whereas hydrogen bonding interactions and van der Waals forces play a major role in the interaction between the compounds and HSA.

show abstract

“…The yields are usually very good and the reaction occurs at room temperature. Depending on the substitution pattern and the solvent/base system used, the reaction time varies from 3 to 20 h [1,11,12]. The system of methanol/NaOH is not suitable for the synthesis of nitro-derivatives nor for the synthesis of 2’-aminochalcones.…”

Section: Experimental Designmentioning

confidence: 99%

Synthesis Chalones and Their Isomerization into Flavanones and Azaflavanones

Rocha

Vaz

Pinto

et al. 2019

MPs

Self Cite

View full text Add to dashboard Cite

Flavanones [2-aryl-2,3-dihydrochromen-4(1H)ones] and 2-aryl-2,3-dihydroquinolin-4(1H)-ones are valuable precursors in the synthesis of important pharmacological scaffolds, so efficient methodologies towards their synthesis are important in the medicinal chemistry context. Their synthesis also involves theoretical concepts such as aldol condensation, isomerization, and catalysis that make it useful in an undergraduate organic chemistry laboratory. The use of both microwave irradiation as a source of energy to promote reactions and efficient catalysts are considered within green chemistry principles, mostly because the reaction yields are improved and reaction time decreased. In this paper, the efficiency of microwave irradiation use in the synthesis of chalcone derivatives and efficient catalyst systems to promote their isomerization into flavanones and 2-aryl-2,3-dihydroquinolin-4(1H)-ones is demonstrated.

show abstract

NMR and Structural and Conformational Features of 2′-Hydroxychalcones and Flavones

Cited by 31 publications

References 18 publications

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

Interaction of 4′-methylflavonoids with biological membranes, liposomes, and human albumin

Synthesis Chalones and Their Isomerization into Flavanones and Azaflavanones

Contact Info

Product

Resources

About