One-pot synthesis and radical scavenging activity of novel polyhydroxylated 3-arylcoumarins

Novel N,N′-Disubstituted Acylselenoureas as Potential Antioxidant and Cytotoxic Agents

“…DPPH assay was performed as described by Svinyarov [58]. Briefly, each compound was initially dissolved in absolute methanol at a concentration of 1 mg/mL, and serial dilutions were prepared.…”

A Synthetic Route to 3‐(Heteroaryl)‐7‐hydroxycoumarins Designed for Biosensing Applications

“…Numerous synthetic methods are currently available for the preparation of 3‐(heteroaryl)coumarins [especially 3‐(2‐benzimidazolyl) derivatives]. These include Pechmann, Perkin, or Knoevenagel reactions,14,17 Pd‐catalyzed cross‐coupling reactions,18 condensation reactions of 2‐chloro‐2‐arylacetaldehyde with salicylaldehyde catalyzed by N ‐heterocyclic carbenes (NHC),19 BBr 3 ‐induced domino reactions starting from homophthalic anhydride and a 2‐methoxybenzaldehyde derivative,20 and acid‐catalyzed condensation reactions between an ortho ‐phenylenediamine derivative and a 3‐(ethoxycarbonyl)coumarin 21. However, most of these methods are not really suitable for the introduction of charged functional groups into the heteroaryl moiety, and they are not easily transferable to more sensitive 7‐hydroxycoumarin derivatives.…”

3-(3,4-Dihydroxyphenyl)-8-hydroxy-2H-chromen-2-one

“…Scheme 2) consisting of five sequential steps, including demethylation, lactone ring opening, elimination, isomerization, lactone ring closure and decarboxylation reactions. The main part of this mechanism was deduced on the base of our previous experiments (for details see [10]) and the starting diastereomeric mixture of cis-and trans-3-(2,3-dimethoxyphenyl)-6,7-dimethoxy-1-oxoisochroman-4-carboxylic acids (1) was obtained in 10 min from 6,7-dimetoxihomophthalic anhydride and 2,3-dimethoxybenzaldehyde in presence of DMAP/CH2Cl2 [8][9][10][11]. It has to be also mentioned that the target coumarin 3 was isolated in a high purity (>99%) and yield (92%) just by filtration at the end of the reaction, the latter suggesting the proposed reaction credible for the synthesis of a series of polyhydroxylated coumarin derivatives from readily available starting materials at a low cost.…”

“…In a recent our articles, we demonstrated that polyhydroxylated cis-restricted stilbenes [8,9] or 3-arylcoumarins (2) bearing carboxylic function in their structure [10] can be obtained via one-pot procedure from diastereomeric mixture of methoxylated cis-and trans-3-aryl-3,4-dihydroisocoumarin-4-carboxylic acids [11] by treatment with BBr3. However, just recently we observed that replacement of BBr3 with HBr as a demethylating agent leads to a subsequent reaction, which produces decarboxylated 3-arylcoumarin derivative-the title compound 3 (Scheme 1).…”