Search

Multicomponent reactions (MCRs) represent very interesting tools to reach eco-friendly and sustainable transformations in organic chemistry. In particular, the Biginelli reaction furnishes a very easy approach to the synthesis of a library of biological active compounds in an academic course. Here we describe the realization of several experiments involving the synthesis of potential inhibitors of [beta]-secretase by the Biginelli reaction. All of the obtained compounds were tested with a FRET fluorimetric assay. The experiments were proposed to students either at entry level or during advanced laboratory courses of organic and bioorganic chemistry. The learning objectives at the advanced level were to introduce the students to the practice of combinatorial synthesis and to the evaluation of biological activity of combinatorial libraries by enzyme inhibition assays. The meeting of the learning objectives was probed first by analyzing their daily performance in the laboratory and their increasing proactive attitude, and the contents of their final presentations. The resulting marks obtained by the students were compared with the average evaluation of their career. Second, the students were asked to evaluate the course and their own experience, and the outcome of their evaluation was compared with that of the teachers.

Herein the reaction of methy cinnamates with N‐Iodosuccinimide (NIS) is reported and the possible formation of dihydrobenzofuryl dimeric derivatives (DHBF), known for their biological activities, is explored. Having an oxidizing capacity, we studied the behavior of NIS with methyl ferulate and under optimized reaction conditions we obtained its DHBF dimer in 35% yield. It is worth to note that we did not obtain the DHBF in his natural form, but rather as the demethylated compound, likely due to dismutation reactions activated by the presence of water in the solvent. Methyl caffeate reacted with NIS to furnish the DHBF dimer in 15% yield, while methyl coumarate and methyl isoferulate did not give any form of DHBF dimers, showing the importance of a hydroxyl group in para position on an activated system and an electron‐rich aromatic ring. An electrochemical investigation by cyclic voltammetry was carried out on the three cinnamates and confirmed the correlation between dimerization and oxidation potential: methyl ferulate and methyl caffeate dimerize, while methyl coumarate, due to its higher oxidizing potential, does not. [ABSTRACT FROM AUTHOR]

Permethylated anigopreissin A (PAA), a fully protected form of the natural anigopreissin A, was found in our previous study to be active against several cancer cells, up to IC50 0.24 μM for HepG2 cells. Herein, a total of thirteen PAA analogues with variations in the number, position of substituents and unsaturation were synthesised starting from a common precursor, and their ability to induce cell growth inhibition was tested. By comparing the antiproliferative effect of the analogues with PAA and with the help of computational studies, we have gained valuable insights into both the biological activity and structure of this natural class of compounds. Indeed, we discovered the importance of the C-3 ring in modulating the biological activity of PAA, as well as the crucial role of the trans configuration of the styryl double bond and the significance of substitutions on the other parts of the molecule. [ABSTRACT FROM AUTHOR]

The continuous emergence of SARS-CoV-2 variants caused the persistence of the COVID-19 epidemic and challenged the effectiveness of the existing vaccines. The viral proteases are the most attractive targets for developing antiviral drugs. In this scenario, our study explores the use of HIV-1 protease inhibitors against SARS-CoV-2. An in silico screening of a library of HIV-1 proteases identified four anti-HIV compounds able to interact with the 3CLpro of SARS-CoV-2. Thus, in vitro studies were designed to evaluate their potential antiviral effectiveness against SARS-CoV-2. We employed pseudovirus technology to simulate, in a highly safe manner, the adsorption of the alpha (α-SARS-CoV-2) and omicron (ο-SARS-CoV-2) variants of SARS-CoV-2 and study the inhibitory mechanism of the selected compounds for cell–virus interaction. The results reported a mild activity against the viral proteases 3CLpro and PLpro, but efficient inhibitory effects on the internalization of both variants mediated by cathepsin B/L. Our findings provide insights into the feasibility of using drugs exhibiting antiviral effects for other viruses against the viral and host SARS-CoV-2 proteases required for entry. [ABSTRACT FROM AUTHOR]

Various polysubstituted benzofurans were reduced by using triethylsilane in trifluoracetic acid. 2,3-Dihydrobenzofurans or bibenzyl compounds were obtained in high yields, depending on the nature of the substituents at C2 and on the benzene ring of the core structure. A p -anisole substituent at C2 of benzofurans always led to the corresponding bibenzyls. [ABSTRACT FROM AUTHOR]

This review gives an overview on recent developments in methods for the construction of compounds with the 2,3-dihydrobenzo-furan core in the period 2012 to 2019. Interest in 2,3-dihydrobenzofurans is constantly increasing. The methods are divided into intermolecular and intramolecular approaches. Intermolecular approaches are subdivided according to the parent intermediate for the key reaction, while intermolecular approaches are subdivided according by which bond is formed in the key reaction. The transformation of benzofurans to dihydrobenzofurans and other miscellaneous methods are also discussed. Approaches useful for the synthesis of natural products are emphasized. 1 Introduction 2 Intermolecular Approaches 2.1 o -Quinone Methides and o -Quinones 2.2 p -Quinone Methides and p -Quinones 2.3 Nitrogen-Containing Phenols and Quinones 2.4 o -Hydroxyphenylcarbonyl Derivatives and Phenols 2.5 Miscellaneous 3 Intramolecular Approaches 3.1 O–C2 Bond Forming 3.2 C2–C3 Bond Forming 3.3 C3–Aryl Bond Forming 3.4 O–Aryl Bond Forming 4 From BF to DHB 5 Rearrangements and Aromatizations [ABSTRACT FROM AUTHOR]

A convergent approach for the synthesis of (±)-myricanol, a strained diarylheptanoid isolated from Myricacae , was undertaken using a Suzuki–Miyaura coupling followed by a ring-closing metathesis (RCM). Herein, we report the unintentional formation of a 26-membered macrocycle as RCM product resulting from a head-to-tail dimerization of the seco -precursor, even in relay ring-closing metathesis (RRCM) conditions. [ABSTRACT FROM AUTHOR]

The preparation and characterization of conformationally well-defined ketal compounds which exhibit medium-high optical rotation (OR) values and are independent of the solvent, and electronic circular dichroism (ECD) spectra is reported. The compounds were obtained through reaction between flexible and optically transparent molecules such as 1,2-, syn- and anti-1,3-diols, 1,3-sulfanylalcohols with fluorenone dimethyl acetal.

The first example of an efficient enantioselective preparation of a chiral calix[4]arene bis-epoxide via a direct asymmetric reaction on the parent 1,3-diformylcalix[4]arene is reported. The results from the [super 1]H and [super 13]C NMR analyses reveal the presence of two biaryl epoxides in obtained compounds.

The convergent synthesis of the lower part of C12-C24 of macrolactin A is explained. The disconnections at the lactone bond and the C11-C12 bond to produce upper and lower moieties are proposed.