6-Endo Heck Cyclization of 3-(2-Iodophenoxy)methylbenzofurans: A Useful Approach to Pterocarpenes

Isolation, Characterization, In Vitro and In Silico Assessment of Undescribed Bioactive Constituents from Pterocarpus santalinus L. Heartwood

Pterocarpus santalinus heartwood is well acknowledged for its medicinal properties and use in the furniture and handicraft industries. Owing to its medicinal properties, the present investigation aims to isolate and characterize the secondary metabolites from the heartwood. The investigation led to the isolation of one undescribed dehydropterocarpan and eleven known compounds. P. santalinusheartwood is found to be a new source for six compounds. Interestingly, the undescribed dehydropterocarpan is transformed into an artifact, which led us to understand the biosynthetic correlations. The isolated compounds displayed moderate inhibition of α-glucosidase and α-amylase. The enzymatic assay outcome is further complimented with the in silico docking analysis. We have also evaluated the compounds for their drug-likeness properties, which align with the desired characteristics of potential drug candidates.

Pd-catalyzed annulation of imidazo[1,2-a]pyridines with coumarins and indoles: synthesis of benzofuran and indole fused heterocycles

Palladium-catalyzed annulation of imidazo[1,2-a]pyridines with coumarins provided benzofuran fused transannulated products in good to excellent yields via a decarbonylative approach, while imidazo[1,2-a]pyridines with N-methyl indoles in the presence of palladium and base yielded conjugated imidazopyridine fused indole derivatives. Additional experiments revealed that the presence of the phenyl ring at the C-2 position of imidazo[1,2-a]pyridines is essential for the annulation than the alkyl groups. Both transformations follow the ionic mechanism by Pd-catalyzed double C-H bond activation. All the annulated products were shown to exhibit high fluorescence characteristics and their photophysical properties were evaluated.

Chemistry of 3-hydroxy-2-aryl acrylate: syntheses, mechanisms, and applications

3-Hydroxy-2-aryl acrylate is important scaffold which is widely used for the synthesis of pharmacologically active compounds. This review summarises the synthetic methods of the 3-hydroxy-2-aryl acrylate including mechanisms and applications.

Collective Syntheses of 2-(3-Methylbenzofuran-2-yl)phenol-Derived Natural Products by a Cascade [3,3]-Sigmatropic Rearrangement/Aromatization Strategy

A cascade [3,3]-sigmatropic rearrangement/aromatization strategy to the synthesis of 2-(3-methylbenzofuran-2-yl)phenol derivatives was developed and applied to the collective syntheses of seven 2-arylbenzofuran-containing natural products, namely glycybenzofuran, glycyuralin E, lespedezol A₁, puerariafuran, 7,2',4'-trihydroxy-3-benzofurancarboxylic acid, coumestrol, and 4'-O-methylcoumestrol. Among them, the total syntheses of glycybenzofuran, glycyuralin E, puerariafuran, 7,2',4'-trihydroxy-3-benzofurancarboxylic acid, and 4'-O-methylcoumestrol were reported for the first time. The practicality of this novel strategy in preparation of the key intermediates was demonstrated by performing the reaction on gram scale and by synthesizing a series of natural products with 2-(3-methylbenzofuran-2-yl)phenol scaffolds in a common strategy.

Syntheses of pterocarpenes and coumestans via regioselective cyclodehydration

A highly efficient synthetic route to pterocarpenes and coumestans is described. BCl3-mediated dehydrative cyclization of 1,3-diaryloxyacetones under mild conditions permitted regioselective ring closure to afford 3-((2-iodoaryloxy)methyl)benzofurans which were converted to the corresponding pterocarpenes by Pd-catalyzed intramolecular direct arylation. The subsequent benzylic oxidation led to coumestans. This sequence was applied to the formal syntheses of coumestrol and the proposed structure of plicadin as well as total syntheses of flemichapparins B and C.

Practical synthesis and cytotoxic evaluation of the pyrazino[1,2-b]-isoquinoline ring system

A multicomponent three-step synthesis of pyrazino[1-2b]isoquinolines is described. A preliminary cytotoxic screening against cancer cell lines was performed.

Palladium-catalyzed α-arylation of aryloxyketones for the synthesis of 2,3-disubstituted benzofurans

A highly efficient palladium-catalyzed α-arylation of aryloxyketones has been developed, allowing for facile installation of various (hetero)aryl groups at C2 position in good to excellent yields. Subsequent cyclodehydration of the resulting α-arylated aryloxyketones provided rapid access to diverse 2,3-disubstitured benzofurans.