Photochemical C-H acetalization of O-heterocycles utilizing phenylglyoxylic acid as the photoinitiator.

A novel, mild, metal-free and easy-to-execute procedure for the C-H acetalization of O-heterocycles via visible light activation is presented, utilizing phenylglyoxylic acid as the photoinitiator. Biomass-derived O-heterocycles, like THF, can be employed, while primary, secondary alcohols and alcohols bearing a variety of functionalities were succesfully employed, affording the desired acetals in high yields. Facile acidic deprotection was also performed.

Nitro Fatty Acids (NO2-FAs): An Emerging Class of Bioactive Fatty Acids.

Unsaturated nitro fatty acids (NO2-FAs) constitute a category of molecules that may be formed endogenously by the reaction of unsaturated fatty acids (UFAs) with secondary species of nitrogen monoxide and nitrite anions. The warhead of NO2-FAs is a nitroalkene moiety, which is a potent Michael acceptor and can undergo nucleophilic attack from thiol groups of biologically relevant proteins, showcasing the value of these molecules regarding their therapeutic potential against many diseases. In general, NO2-FAs inhibit nuclear factorκ-B (NF-κB), and simultaneously they activate nuclear factor (erythroid derived)-like 2 (Nrf2), which activates an antioxidant signaling pathway. NO2-FAs can be synthesized not only endogenously in the organism, but in a synthetic laboratory as well, either by a step-by-step synthesis or by a direct nitration of UFAs. The step-by-step synthesis requires specific precursor compounds and is in position to afford the desired NO2-FAs with a certain position of the nitro group. On the contrary, the direct nitration of UFAs is not a selective methodology; thus, it affords a mixture of all possible nitro isomers.

Identification of a Dual Inhibitor of Secreted Phospholipase A2 (GIIA sPLA2) and SARS-CoV-2 Main Protease.

The development of novel agents to combat COVID-19 is of high importance. SARS-CoV-2 main protease (Mpro) is a highly attractive target for the development of novel antivirals and a variety of inhibitors have already been developed. Accumulating evidence on the pathobiology of COVID-19 has shown that lipids and lipid metabolizing enzymes are critically involved in the severity of the infection. The purpose of the present study was to identify an inhibitor able to simultaneously inhibit both SARS-CoV-2 Mpro and phospholipase A2 (PLA2), an enzyme which plays a significant role in inflammatory diseases. Evaluating several PLA2 inhibitors, we demonstrate that the previously known potent inhibitor of Group IIA secretory PLA2, GK241, may also weakly inhibit SARS-CoV-2 Mpro. Molecular mechanics docking and molecular dynamics calculations shed light on the interactions between GK241 and SARS-CoV-2 Mpro. 2-Oxoamide GK241 may represent a lead molecular structure for the development of dual PLA2 and SARS-CoV-2 Mpro inhibitors.

2-Oxoester Phospholipase A2 Inhibitors with Enhanced Metabolic Stability.

2-Oxoesters constitute an important class of potent and selective inhibitors of human cytosolic phospholipase A2 (GIVA cPLA2) combining an aromatic scaffold or a long aliphatic chain with a short aliphatic chain containing a free carboxylic acid. Although highly potent 2-oxoester inhibitors of GIVA cPLA2 have been developed, their rapid degradation in human plasma limits their pharmaceutical utility. In an effort to address this problem, we designed and synthesized two new 2-oxoesters introducing a methyl group either on the α-carbon to the oxoester functionality or on the carbon carrying the ester oxygen. We studied the in vitro plasma stability of both derivatives and their in vitro inhibitory activity on GIVA cPLA2. Both derivatives exhibited higher plasma stability in comparison with the unsubstituted compound and both derivatives inhibited GIVA cPLA2, however to different degrees. The 2-oxoester containing a methyl group on the α-carbon atom to the oxoester functionality exhibits enhancement of the metabolic stability and retains considerable inhibitory potency.

Visible-Light-Mediated Catalytic Hydroacylation of Dialkyl Azodicarboxylates by Graphite Flakes.

A novel and efficient metal-free catalyzed hydroacylation of dialkyl azodicarboxylates is reported. Graphite flakes were found to be the most efficient catalyst among other carbon-based materials to promote this reaction. This unprecedented catalytic activity can be expanded into a wide substrate scope of aliphatic aldehydes bearing various functional groups, leading to the corresponding products in good to excellent yields.