The merger of electro-reduction and hydrogen bonding activation for a radical Smiles rearrangement.

The reductive activation of chemical bonds at less negative potentials provides a foundation for high functional group tolerance and selectivity, and it is one of the central topics in organic electrosynthesis. Along this line, we report the design of a dual-activation mode by merging electro-reduction with hydrogen bonding activation. As a proof of principle, the reduction potential of -phenylpropiolamide was shifted positively by 218 mV.

Electrochemical quinuclidine-mediated Minisci-type acylation of N-heterocycles with aldehydes.

The electro-generation of acyl radicals from both aromatic and aliphatic aldehydes remains an unmet challenge. We provide a solution to this challenge by merging electro-oxidation and a quinuclidine-mediated hydrogen atom transfer strategy. The generation of acyl radicals at decreased applied potentials compared to that of formyl oxidation exhibits excellent functional group compatibility.

Fucoxanthin restructures the gut microbiota and metabolic functions of non-obese individuals in an fermentation model.

Fucoxanthin, a carotenoid exclusively derived from algae, exerts its bioactivities with the modulation of the gut microbiota in mice. However, mechanisms through which fucoxanthin regulates the gut microbiota and its derived metabolites/metabolism in humans remain unclear. In this study, we investigated the effects of fucoxanthin on the gut microbiota and metabolism of non-obese individuals using an simulated digestion-fermentation cascade model.

Paired Electrolysis Enabled Trifluoromethylheteroaromatization of Alkenes and Alkyne with Trifluoromethyl Thianthrenium Triflate (TT-CFOTf) as a Bifunctional Reagent.

We report a strategic exploitation of trifluoromethyl thianthrenium triflate (TT-CFOTf) as both electromediator and CF radical precursors for paired electrolysis. Enabled by this strategy, the three-component trifluoromethylheteroaromatization of alkenes and alkynes was realized. The superiority of TT-CFOTf to other electrophilic CF reagents is attributed to the cathodic generation of thianthrene (TT) as a mediator, which shifts the heterogeneous oxidation of interest to a homogeneous one.

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NHI.

The electrochemical preparation of 2-aminothiazoles has been achieved by the reaction of active methylene ketones with thioureas assisted by ᴅʟ-alanine using NHI as a redox mediator. The electrochemical protocol proceeds in an undivided cell equipped with graphite plate electrodes under constant current conditions. Various active methylene ketones, including β-keto ester, β-keto amide, β-keto nitrile, β-keto sulfone and 1,3-diketones, can be converted to the corresponding 2-aminothiazoles.

Electrochemical Organoselenium-Catalyzed Intermolecular Hydroazolylation of Alkenes with Low Catalyst Loadings.

The organoselenium-catalyzed amination of alkenes is a promising way to construct functionalized amines. However, the use of chemical oxidants and the unavoidable formation of allylic amine or enamine are the two main limitations of these methodologies. Against this background, we herein report an electro-selenocatalytic regime for the hydroazolylation of alkenes with azoles under external oxidant-free conditions with low catalyst loadings.

A new oleanane-type triterpene from D.Dietr and its cytotoxic activity.

A new oleanane-type triterpene, ardisiapunine (), together with eight known compounds were isolated from the roots of D.Dietr. Their chemical structures were determined by means of spectroscopic methods including HR-ESI-MS and (1 D, 2 D) NMR data.

Electrophotocatalytic C-H Functionalization of N-Heteroarenes with Unactivated Alkanes under External Oxidant-Free Conditions.

The Minisci alkylation of N-heteroarenes with unactivated alkanes under external oxidant-free conditions provides an economically attractive route to access alkylated N-heteroarenes but remains underdeveloped. Herein, a new electrophotocatalytic strategy to access alkyl radicals from strong C(sp )-H bonds was reported for the following Minisci alkylation reactions in the absence of chemical oxidants. This strategy realized the first example of cerium-catalyzed Minisci alkylation reaction directly from abundant unactivated alkanes with excellent atom economy.

Recent advances in organic electrosynthesis employing transition metal complexes as electrocatalysts.

Organic electrosynthesis has been widely used as an environmentally conscious alternative to conventional methods for redox reactions because it utilizes electric current as a traceless redox agent instead of chemical redox agents. Indirect electrolysis employing a redox catalyst has received tremendous attention, since it provides various advantages compared to direct electrolysis. With indirect electrolysis, overpotential of electron transfer can be avoided, which is inherently milder, thus wide functional group tolerance can be achieved.

-Hydroxyphthalimide-Mediated Electrochemical Denitrogenation of Aroylhydrazides to Generate Acyl Radicals and Their Applications in the Syntheses of Fluorenones.

-Hydroxyphthalimide (NHPI)-mediated electrochemical denitrogenation of aroylhydrazides is developed for the first time. The in situ generated acyl radicals could be intramolecularly trapped to give fluorenones with high efficiencies. This electrochemical method features external oxidant- and transition metal-free conditions.

Anodic oxidation triggered divergent 1,2- and 1,4-group transfer reactions of β-hydroxycarboxylic acids enabled by electrochemical regulation.

We report a set of electrochemically regulated protocols for the divergent synthesis of ketones and β-keto esters from the same β-hydroxycarboxylic acid starting materials. Enabled by electrochemical control, the anodic oxidation of carboxylic acids proceeded in either a one-electron or a two-electron pathway, leading to a 1,4-aryl transfer or a semipinacol-type 1,2-group transfer product with excellent chemoselectivity. The 1,4-aryl transfer represents an unprecedented example of carbon-to-oxygen group transfer proceeding a radical mechanism.

Indirect Electrosynthesis with Halogen Ions as Mediators.

Organic electrosynthesis has gained increasing research interest as it harvests electric current as redox regents, thereby providing a sustainable alternative to conventional approaches. Compared with direct electrosynthesis, indirect electrosynthesis employs mediator(s) to lower the overpotentials for substrate activation, and enhance the reaction efficiency and functional group compatibility by shifting the heterogenous electron transfer process to be homogenous. As one of the most versatile and cost-efficient mediators, halogen mediators are always combined with an irreversible halogenation reaction.

Nickel-catalyzed electrochemical reductive decarboxylative coupling of N-hydroxyphthalimide esters with quinoxalinones.

Herein the first example of electrochemically enabled, NiCl-catalyzed reductive decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with quinoxalinones is reported. A range of primary, secondary, tertiary aliphatic carboxylic acids and amino acid-derived esters were tolerated well. This decarboxylative coupling allows access to structurally diverse 3-alkylated quinoxalinones in up to 91% yields.

One-Pot Anodic Conversion of Symmetrical Bisamides of Ethylene Diamine to Unsymmetrical -Bisamides of Methylene Diamine.

Symmetrical bisamides of ethylene diamine of type ArCONHCHCHNHCOAr undergo anodic C-C bond cleavage in acetonitrile-LiClO under controlled-potential electrolysis. The electrogenerated carbocation intermediates react with the solvent acetonitrile to afford unsymmetrical -bisamides of type ArCONHCHNHCOMe in a one-pot reaction. The yields of the latter products are moderate (up to 60%).

Synthesis and anti-tumor activity of [1,4] dioxino [2,3-f] quinazoline derivatives as dual inhibitors of c-Met and VEGFR-2.

Both c-Met and VEGFR-2 were important targets for cancer therapies. In order to develop reversible and non-covalent c-Met and VEGFR-2 dual inhibitors, a series of [1,4]dioxino[2,3-f]quinazoline derivatives were designed and synthesized. The enzyme assay demonstrated that most target compounds had inhibition potency on both c-Met and VEGFR-2 with IC values in nanomolar range especially compounds 7m and 7k.

Electrochemical Dehydrogenative Imidation of N-Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines.

A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain structurally diverse phthalimide-protected gem-diamines.

Electrochemical Formation of N-Acyloxy Amidyl Radicals and Their Application: Regioselective Intramolecular Amination of sp and sp C-H Bonds.

Electrochemical generation of N-acyloxy amidyl radicals via an inner-sphere electron-transfer process is described for the first time. With NaBr as the catalyst and electrolyte, the in situ generated amidyl radicals undergo intramolecular C(sp/sp)-H aminations to give lactams with unprecedented regio- and chemoselectivities. Moreover, the synthetic utility of current method is demonstrated by the synthesis of PJ34 and Phenaglaydon.

A methylene blue-based near-infrared fluorescent probe for rapid detection of hypochlorite in tap water and living cells.

A methylene blue-based near-infrared fluorescent probe was designed for the selective determination of hypochlorite (ClO), over other reactive oxygen species or interfering agents. Acetylated methylene blue was synthesized by introducing the acetyl group into the methylene blue framework, which can specifically recognize exogenous and endogenous ClO. The acetylated methylene blue fluorescent probe was characterized by H NMR, C NMR and HRMS.

Functionalization of -arylglycine esters: electrocatalytic access to C-C bonds mediated by -BuNI.

An efficient electrocatalytic functionalization of -arylglycine esters is reported. The protocol proceeds in an undivided cell under constant current conditions employing the simple, cheap and readily available -BuNI as the mediator. In addition, it is demonstrated that the mediated process is superior to the direct electrochemical functionalization.

Ultrasensitive Tyrosinase-Activated Turn-On Near-Infrared Fluorescent Probe with a Rationally Designed Urea Bond for Selective Imaging and Photodamage to Melanoma Cells.

Melanoma is a highly aggressive malignancy and early monitoring and diagnosis are challenging at present. Tyrosinase is overexpressed in melanoma and regarded as an important biological marker for diagnosis and treatment. Thus, the selective and sensitive detection of tyrosinase is of great significance.

Scalable Electrochemical Dehydrogenative Lactonization of C(sp/sp)-H Bonds.

A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp/sp)-H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol. The remote lactonization of C(sp)-H bonds would constitute an important synthetic advance toward electrochemical C-O bond formation.

Use of Electrochemistry in the Synthesis of Heterocyclic Structures.

The preparation and transformation of heterocyclic structures have always been of great interest in organic chemistry. Electrochemical technique provides a versatile and powerful approach to the assembly of various heterocyclic structures. In this review, we examine the advance in relation to the electrochemical construction of heterocyclic compounds published since 2000 via intra- and intermolecular cyclization reactions.

Electrocatalytic Minisci Acylation Reaction of N-Heteroarenes Mediated by NHI.

An electrochemical C-H acylation of electron-deficient N-heteroarenes with α-keto acids is reported. This first electrochemical Minisci acylation reaction proceeded using NHI as a redox catalyst. A broad N-heteroarene scope and high functional group tolerance are observed.

Synthesis and biological evaluation of novel steroidal 5α,8α-epidioxyandrost-6-ene-3β-ol-17-(O-phenylacetamide)oxime derivatives as potential anticancer agents.

Inspired by the significant anti-cancer activity of our previously screened natural ergosterol peroxide (EP, 1), we synthesized and characterized a series of novel 5α,8α-epidioxyandrost-3β-ol-17-(O-phenylacetamide)oxime derivatives (9a-o). The anti-proliferative activity of the synthesized compounds against human hepatocellular carcinoma cells (HepG2, Sk-Hep1) and human breast cancer cells (MCF-7, MDA-MB231) were investigated. Compounds 9d, 9f, 9h, 9j and 9m displayed good anti-proliferative activity (most IC<20μM) in vitro.

Synthesis and biological evaluation of novel steroidal 5α,8α-endoperoxide derivatives with aliphatic side-chain as potential anticancer agents.

By inspiration of significant anti-cancer activity of our previously screened natural ergosterol peroxide (EP), a series of novel steroidal 5α,8α-endoperoxide derivatives 5a-d and 14a-f were designed, synthesized, and biologically evaluated for their in vitro anti-proliferative inhibitory and cytotoxic activity. The results revealed that most of these compounds showed moderate-to-excellent anti-proliferative effects against the tested cancer cell lines (i.e.