A very simple solvent-free method for the synthesis of 2-arylchromones using KHSO4 as a recyclable catalyst

Efficient synthesis and evaluation of therapeutic potential of fluorine containing 2-arylchromen-4-ones

A large series of 2-arylchromen-4-ones containing from 1 to 3 fluorine atoms or a trifluoromethyl group in the structure was synthesized by condensation of fluorinated 2-hydroxyacetophenones with benzaldehydes in an alkaline medium and subsequent oxidative cyclization of the resulting 2'-hydroxychalcones by action of I2 in DMSO. The cytotoxicity of the obtained compounds was studied in glioblastoma cell line, SNB19, and in a monkey-derived normal kidney epithelium cell line, Vero. In addition, antiglycation activity of the obtained compounds was evaluated. The inhibitory activity of some fluorinated 2-arylchromen-4-ones against acetylcholinesterase, butyrylcholinesterase and carboxylesterase as well their primary antioxidant activity in ABTS and FRAP tests were investigated. Screening of the synthesized compounds for their inhibitory activity against influenza A virus A/Puerto Rico/8/34 (H1N1) in the MDCK cell culture revealed that fluorinated compounds 32, 31 and 39 showed manifest antiviral effects (with IS = 57, 38 and 25 correspondingly) that makes this series of new biologically attractive fluorinated heterocycles promising for further development and in-depth study.

Selectively Halogenated Flavonolignans-Preparation and Antibacterial Activity

A library of previously unknown halogenated derivatives of flavonolignans (silybins A and B, 2,3-dehydrosilybin, silychristin A, and 2,3-dehydrosilychristin A) was prepared. The effect of halogenation on the biological activity of flavonolignans was investigated. Halogenated derivatives had a significant effect on bacteria. All prepared derivatives inhibited the AI-2 type of bacterial communication (quorum sensing) at concentrations below 10 µM. All prepared compounds also inhibited the adhesion of bacteria (Staphyloccocus aureus and Pseudomonas aeruginosa) to the surface, preventing biofilm formation. These two effects indicate that the halogenated derivatives are promising antibacterial agents. Moreover, these derivatives acted synergistically with antibiotics and reduced the viability of antibiotic-resistant S. aureus. Some flavonolignans were able to reverse the resistant phenotype to a sensitive one, implying that they modulate antibiotic resistance.

Propyl Gallate

The title compound, propyl gallate (III), is an important substance popularly used in the food, cosmetic and pharmaceutical industries. Current chemical syntheses of this compound are based on the acylation supported by thionyl chloride, DIC/DMAP or Fischer esterification using a range of homogenous and heterogenous catalysts. In this paper, an efficient, green, straightforward, and economical method for synthesizing propyl gallate using potassium hydrogen sulfate, KHSO4, as the heterogenous acidic catalyst has been developed for the first time. In addition, this paper provides a comprehensive spectral dataset for the title compound, especially the new data on DEPT and 2D NMR (HSQC and HMBC) spectra which are not currently available in the literature.

A novel one-pot synthesis of flavones

In this paper, a one-pot facile route for the BiCl₃/RuCl₃-mediated synthesis of functionalized flavones is described, including: (i) intermolecular ortho-acylation of substituted phenols with cinnamoyl chlorides, and (ii) intramolecular cyclodehydrogenation of the resulting o-hydroxychalcones. The reaction conditions are discussed herein.

A one-pot facile route for the BiCl₃/RuCl₃-mediated synthesis of functionalized flavones is described, including: (i) ortho-acylation of phenols with cinnamoyl chlorides, and (ii) cyclodehydrogenation of the resulting o-hydroxychalcones.