Bioinspired nonheme iron complex that triggers mitochondrial apoptotic signalling pathway specifically for colorectal cancer cells

The activation of dioxygen is the keystone of all forms of aerobic life. Many biological functions rely on the redox versatility of metal ion to perform reductive activation-mediated processes entailing...

Research of corrosion fracture of D16t and AMg6 aluminum alloys exposed to microscopic fungi

This paper presents an experimental study of biocorrosion of D16T and AMg6 aluminum alloys. The determining role of reactive oxygen species in aluminum biocorrosion by a consortium of molds has been shown. A model is proposed, according to which the initiators of corrosion damage to the metal surface are superoxide anion radical and hydrogen peroxide released during the life of micromycetes. It is assumed that the initiation and development of biocorrosion occurs, among other things, as a result of the process of reductive activation of oxygen and the Fenton decomposition of hydrogen peroxide. A conclusion is made about the mechanism of the occurrence of intergranular and pitting corrosion of aluminum alloys interacting with microscopic fungi.

Bifunctional N-Aminopyridinium Reagents Enable C–H Amination, Olefin Carboamination Cascades

<div> <div> <div> <p>C–H amination reactions provide streamlined access to nitrogen-containing small molecules. Here, we disclose benzylic C–H amination with N-aminopyridiniums, which are bifunctional reagents that provide avenues for further diversification. Reductive activation of the incipient N–N bonds unveils electrophilic N-centered radicals, which can be engaged by nucleophilic partners such as olefins, silyl enol ethers, and electron-rich heterocycles. We highlight the synthetic potential of these sequences in the synthesis of tetrahydroisoquinolines, which are important heterocycles in molecular therapeutics, via anti-Markovnikov olefin carboamination. Unlike many C–H amination reactions that provide access to protected amines, the current method installs an easily diversifiable synthetic handle that serves as a lynchpin for C–H amination, deaminative N–N functionalization sequences. </p> </div> </div> </div>

Bifunctional N-Aminopyridinium Reagents Enable C–H Amination, Olefin Carboamination Cascades

<div> <div> <div> <p>C–H amination reactions provide streamlined access to nitrogen-containing small molecules. Here, we disclose benzylic C–H amination with N-aminopyridiniums, which are bifunctional reagents that provide avenues for further diversification. Reductive activation of the incipient N–N bonds unveils electrophilic N-centered radicals, which can be engaged by nucleophilic partners such as olefins, silyl enol ethers, and electron-rich heterocycles. We highlight the synthetic potential of these sequences in the synthesis of tetrahydroisoquinolines, which are important heterocycles in molecular therapeutics, via anti-Markovnikov olefin carboamination. Unlike many C–H amination reactions that provide access to protected amines, the current method installs an easily diversifiable synthetic handle that serves as a lynchpin for C–H amination, deaminative N–N functionalization sequences. </p> </div> </div> </div>

General α-Amino 1,3,4-Oxadiazole Synthesis via Late-Stage Reductive Functionalization of Tertiary Amides and Lactams

An iridium-catalyzed reductive three-component coupling reaction for the synthesis of medicinally relevant α-amino 1,3,4-oxadiazoles from abundant tertiary amides or lactams, carboxylic acids, and (N-isocyanimino) triphenylphosphorane, is described. Proceeding under mild conditions using (<1 mol%) Vaska’s complex (IrCl(CO)(PPh₃)₂) and tetramethyldisiloxane to access the key reactive iminium ion intermediates, a broad range of structurally complex α-amino 1,3,4-oxadiazole architectures were efficiently accessed from diverse carboxylic acid feedstock coupling partners. Extension to α-amino heterodiazole synthesis was readily achieved by exchanging the carboxylic acid coupling partner for C-, S-, or N-centered Brønsted acids, and provided rapid and modular access to these desirable, yet difficult-to-access, heterocycles. Furthermore, the high chemoselectivity of the catalytic reductive activation step allowed the late-stage functionalization of 10 drug molecules, including the synthesis of novel heterodiazole-fused drug-drug conjugates.<br>

General α-Amino 1,3,4-Oxadiazole Synthesis via Late-Stage Reductive Functionalization of Tertiary Amides and Lactams

An iridium-catalyzed reductive three-component coupling reaction for the synthesis of medicinally relevant α-amino 1,3,4-oxadiazoles from abundant tertiary amides or lactams, carboxylic acids, and (N-isocyanimino) triphenylphosphorane, is described. Proceeding under mild conditions using (<1 mol%) Vaska’s complex (IrCl(CO)(PPh₃)₂) and tetramethyldisiloxane to access the key reactive iminium ion intermediates, a broad range of structurally complex α-amino 1,3,4-oxadiazole architectures were efficiently accessed from diverse carboxylic acid feedstock coupling partners. Extension to α-amino heterodiazole synthesis was readily achieved by exchanging the carboxylic acid coupling partner for C-, S-, or N-centered Brønsted acids, and provided rapid and modular access to these desirable, yet difficult-to-access, heterocycles. Furthermore, the high chemoselectivity of the catalytic reductive activation step allowed the late-stage functionalization of 10 drug molecules, including the synthesis of novel heterodiazole-fused drug-drug conjugates.<br>