Structural Similarity in Natural Products Leading to Sample Misidentification: A Case Study of the Bisbenzylisoquinoline Alkaloids Oxyacanthine and Berbamine.

The similar structures of natural compounds and the absence of NMR data for commercial products raise the risk of misidentification. This work reports a case in which purchased samples labeled as "berbamine" from 14 suppliers are oxyacanthine (). The NMR data of all purchased samples were consistent.

Effect of electron beam irradiation treatment on microstructure, physicochemical properties, and bioactive content of areca nut.

Background: Electron beam irradiation treatment is a novel technology that uses low-dose ionizing radiation for the treatment of crops or food to enhance their quality. This study investigated the effects of electron beam irradiation on the microstructure, physicochemical properties, and bioactive compounds of areca nuts.

Results: As the irradiation dose increased, the cellulose, hemicellulose, and lignin content in the areca nuts decreased significantly, whereas the polysaccharide and pectin content increased gradually.

Impurity study of tecovirimat.

This article delineates the systematic identification, synthesis, and impurity control methods used during the manufacturing process development of tecovirimat, an antiviral drug that treats monkeypox. Critical impurities were synthesized, and their chemical structure was confirmed through NMR analysis, GC, and HPLC mass spectrometry. The results established a thorough approach to identify, address, and control impurities to produce high-quality tecovirimat drug substance in accordance with International Conference on Harmonization (ICH)-compliant standards.

An Alternative Approach to Synthesize Sildenafil via Improved Copper-Catalyzed Cyclization.

A facile synthetic pathway for sildenafil has been developed. This approach is characterized by a ligand-free Ullmann-type copper-catalyzed coupling reaction to construct sildenafil and its derivative, pyrrazolo[4,3-]pyrimidin-7-one ring, with yields of 79% and 82%, respectively, in a convergent fashion by connecting key building blocks halo-pyrazole moiety with 2-ethoxybenzamidine and 2-ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]benzamidine in a one-pot reaction. Thus, this approach circumvents the need to use nitric/sulfuric acid for nitration, a costly Pd-catalyst for reduction, and coupling agents encountered in the reported processes.

Direct esterification of amides by the dimethylsulfate-mediated activation of amide C-N bonds.

Amides are important intermediates in organic chemistry and the pharmaceutical industry, but their low reactivity requires catalysts and/or severe reaction conditions for esterification. Here, a novel approach was devised to convert amides into esters without the use of transition metals. The method effectively overcomes the inherent low reactivity of amides by employing dimethylsulfate-mediated reaction to activate the C-N bonds.

Improved and ligand-free copper-catalyzed cyclization for an efficient synthesis of benzimidazoles from -bromoarylamine and nitriles.

We present an improved copper-catalyzed cyclization for an efficient synthesis of benzimidazoles from -bromoarylamine and nitriles, under mild and ligand-free conditions. The optimal conditions yielded exceptional products of up to 98%, demonstrating the broad applicability of this synthetic strategy in generating a wide range of valuable imidazole derivatives. This methodology enables the efficient synthesis of various substituted benzimidazole derivatives and offers an environmentally friendly alternative to conventional methods.

Facile Synthesis of Benzimidazoles via -Arylamidoxime Cyclization.

A facile synthesis of benzimidazoles was described by a one-pot process containing acylation-cyclization of -arylamidoxime. This method provided an alternative synthesis of benzimidazoles with a certain diversity of substituted groups in acceptable yields (up to 96%). More importantly, the construction of bis-benzimidazole (), the key intermediate for making telmisartan, was achieved by adopting this method that enabled avoiding the undesired nitration with nitric/sulfuric acid and the cyclization in polyphosphoric acid in the existing operations.