Mechanistic Investigation of the Ce(III) Chloride Photoredox Catalysis System: Understanding the Role of Alcohols as Additives.

Photocatalytic C-H activation is an emerging area of research. While cerium chloride photocatalysts have been extensively studied, the role of alcohol additives in these systems remains a subject of ongoing discussion. It was demonstrated that the photocatalyst [NEt][CeCl] () produces •Cl and added alcohols exhibit zero-order kinetics.

Optical control of sphingolipid biosynthesis using photoswitchable sphingosines.

Sphingolipid metabolism comprises a complex interconnected web of enzymes, metabolites and modes of regulation that influence a wide range of cellular and physiological processes. Deciphering the biological relevance of this network is challenging as numerous intermediates of sphingolipid metabolism are short-lived molecules with often opposing biological activities. Here, we introduce clickable, azobenzene-containing sphingosines, termed caSphs, as light-sensitive substrates for sphingolipid biosynthesis.

Optical Control of TRPM8 Channels with Photoswitchable Menthol.

Transient receptor potential melastatin 8 (TRPM8) channels are well known as sensors for cold temperatures and cooling agents such as menthol and icilin and these channels are tightly regulated by the membrane lipid phosphoinositol-4,5-bisphosphate (PIP). Since TRPM8 channels emerged as promising drug targets for treating pain, itching, obesity, cancer, dry eye disease, and inflammation, we aimed at developing a high-precision TRPM8 channel activator, to achieve spatiotemporal control of TRPM8 activity with light. In this study, we designed, synthesized and characterized the first photoswitchable TRPM8 activator azo-menthol (AzoM).

Structure and Function of Sabinene Synthase, a Monoterpene Cyclase That Generates a Highly Strained [3.1.0] Bicyclic Product.

Sabinene is a plant natural product with a distinctive strained [3.1.0] bicyclic ring system that is used commercially as a spicy and pine-like fragrance with citrus undertones.

Smiles-Rearrangement-Based One-Pot Synthesis of Diarylacetylenes from Benzylic Sulfones and Methyl Benzoates Mediated by LiN(SiMe)/KN(SiMe).

The one-pot synthesis of diphenylacetylene by the reaction of methyl benzoate with 1-(benzylsulfonyl)-3,5-di(trifluoromethyl)benzene was developed. The combination of LiN(SiMe) and KN(SiMe) is key to promoting the reaction. Simply combining methyl benzoate, 1-(benzylsulfonyl)-3,5-di(trifluoromethyl)benzene, LiN(SiMe), and KN(SiMe) can produce a variety of diaryl acetylenes (28 examples, 18-70% yields).

Optical control of sphingolipid biosynthesis using photoswitchable sphingosines.

Sphingolipid metabolism comprises a complex interconnected web of enzymes, metabolites and modes of regulation that influence a wide range of cellular and physiological processes. Deciphering the biological relevance of this network is challenging as numerous intermediates of sphingolipid metabolism are short-lived molecules with often opposing biological activities. Here, we introduce clickable, azobenzene-containing sphingosines, termed s, as light-sensitive substrates for sphingolipid biosynthesis.

Enantioselective Synthesis of Aminals Via Nickel-Catalyzed Hydroamination of 2-Azadienes with Indoles and N-Heterocycles.

New methods for the enantioselective synthesis of N-alkylated indoles and their derivatives are of great interest because indoles are pivotal structural elements in biologically active molecules and natural products. They are also versatile intermediates in organic synthesis. Among well-established asymmetric hydroamination methods, the asymmetric hydroamination with indole-based substrates is a formidable challenge.

Thioamide-based fluorescent sensors for dipeptidyl peptidase 4.

Dipeptidyl peptidase 4 (DPP-4) is a promising biomarker for cancer and metabolic diseases. We demonstrate the design of novel fluorescent DPP-4 probes based on the protease's native substrates using a thioamide as a quencher for measuring kinetics, inhibition with sitagliptin, and DPP-4 activity in saliva samples.

Design, Synthesis, and Structural Evaluation of Acetylated Phenylthioketone Inhibitors of HDAC10.

Histone deacetylase 10 (HDAC10) is unique among the greater HDAC family due to its unusually narrow substrate specificity as a polyamine deacetylase, specifically as an -acetylspermidine hydrolase. Polyamines are essential for cell growth and proliferation; consequently, inhibition of polyamine deacetylation represents a possible strategy for cancer chemotherapy. In this work, we have designed six acetylated phenylthioketone inhibitors of HDAC10 containing positively charged - and -substituted amino groups designed to target interactions with E274, the gatekeeper that recognizes the positively charged ammonium group of the substrate -acetylspermidine.

Controlling the Size of Molecular Copper Clusters Supported by a Multinucleating Macrocycle.

The use of a nonrigid, pyridyldialdimine-derived macrocyclic ligand (PDAI) enabled the synthesis of well-defined mono-, di-, tri-, and tetra-nuclear Cu(I) complexes in good yields through rational synthetic means. Starting from mono- and diargentous PDAI complexes, transmetalation to Cu(I) proceeded smoothly with formation of AgX (X = Cl, I) salts to generate mono-, di-, and trinuclear copper complexes. Monodentate supporting ligands (MeCN, xylNC, PMe, PPh) were found to either transmetallate with or bind various di- and trinuclear clusters.

Cell-Specific Optical Control of AMPA Glutamate Receptors with a Photoswitchable Tethered Antagonist.

AMPA receptors (AMPARs) are the main drivers of excitatory glutamatergic transmission in the brain, central to synaptic plasticity, and are key drug targets. However, AMPARs are expressed in virtually every neuron in the central nervous system and are activated with complex temporal dynamics, making it difficult to determine their functional roles with sufficient precision. Here we describe a cell specific, light-controllable competitive antagonist for the AMPA receptor called MP-GluA that combines the temporal precision of a photo-switchable ligand with the spatial and cellular specificity of a genetically-encoded membrane-anchor protein.

Non-Small Cell Lung Cancer Imaging Using a Phospholipase A2 Activatable Fluorophore.

Lung cancer, the most common cause of cancer-related death in the United States, requires advanced intraoperative detection methods to improve evaluation of surgical margins. In this study we employed DDAO-arachidonate (DDAO-A), a phospholipase A2 (PLA2) activatable fluorophore, designed for the specific optical identification of lung cancers in real-time during surgery. The fluorescence activation of DDAO-A by porcine sPLA2 was tested in various liposomal formulations, with 100 nm extruded EggPC showing the best overall characteristics.

Synthesis and Luminescence Studies of a Tethered, Trigonal, Silver(I) Tris(alkyne) Complex.

The synthesis and characterization of a tris(alkyne) ligand, tris[2-(trimethylsilyl)ethynyl-4--butylbenzyl]amine (), and its silver(I) hexafluorophosphate complex, , are reported. The solid-state structure and luminescence properties of indicate relatively strong silver(I)-alkyne interactions between the metal cation and . No significant changes in the bond angles or lengths were observed upon metalation of with Ag, indicating a relatively unstrained ligand-metal motif.

Assembly of a trapped valent Ce-TCNQ complex through metal-ligand redox cooperativity.

Complex (CpCe)(TCNQ)(CeCp) (1) was prepared by reducing neutral TCNQ (tetracyanoquinodimethane) with CpCe(THF). Two types of cerium centres with a dianionic TCNQ moiety are present in 1, wherein each of the four cyano-groups are bound by a cation. Formation of this trapped-valent organocerium compound 1 is facilitated by metal-ligand redox cooperativity.

A Vanadium Methylidene.

Examples of stable 3d transition metal methylidene complexes are extremely rare. Here we report an isolable and stable vanadium methylidene complex, [(PNP)V(=NAr)(=CH)] (PNP = N[2-PPr-4-methylphenyl], Ar = 2,6-PrCH), via H atom transfer (HAT) from [(PNP)V(NHAr)(CH)] or [(PNP)V(=NAr)(CH)] using two or one equivalents of the TEMPO radical (TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl), respectively. Alternatively, the vanadium methylidene moiety can also be formed via the treatment of transient [(PNP)V=NAr] with the Wittig reagent, HCPPh.

Methyl-β-cyclodextrin asymmetrically extracts phospholipid from bilayers, granting tunable control over differential stress in lipid vesicles.

Lipid asymmetry - that is, a nonuniform lipid distribution between the leaflets of a bilayer - is a ubiquitous feature of biomembranes and is implicated in several cellular phenomena. Differential tension - that is, unequal lateral monolayer tensions comparing the leaflets of a bilayer- is closely associated with lipid asymmetry underlying these varied roles. Because differential tension is not directly measurable in combination with the fact that common methods to adjust this quantity grant only semi-quantitative control over it, a detailed understanding of lipid asymmetry and differential tension are impeded.

Base-Promoted Synthesis of Isoquinolines through a Tandem Reaction of 2-Methyl-arylaldehydes and Nitriles.

A convenient method for preparing 3-aryl isoquinolines via a base-promoted tandem reaction is presented. Simply combining commercially available 2-methyl-arylaldehydes, benzonitriles, NaN(SiMe), and CsCO enabled the synthesis of a variety of isoquinolines (23 examples, ≤90% yield). Among the syntheses of isoquinolines, the transition metal-free method described here is straightforward, practical, and operationally simple.

Sulfonamides as N-Centered Radical Precursors for C-N Coupling Reactions To Generate Amidines.

Nitrogen-centered radicals (NCRs) are valuable intermediates for the construction of C-N bonds. Traditional methods for the generation of NCRs employ toxic radical initiators, transition metal catalysts, photocatalysts, or organometallic reagents. Herein, we report a novel strategy for the generation of NCRs toward the construction of C-N bonds under transition-metal-free conditions.

Highly tunable bimane-based fluorescent probes: design, synthesis, and application as a selective amyloid binding dye.

Small molecule fluorescent probes are indispensable tools for a broad range of biological applications. Despite many probes being available, there is still a need for probes where photophysical properties and biological selectivity can be tuned as desired. Here, we report the rational design and synthesis of a palette of fluorescent probes based on the underexplored bimane scaffold.

Fungal Planet description sheets: 1478-1549.

Novel species of fungi described in this study include those from various countries as follows: , on whitefly, on bark of , from soil under , on leaf spot of , and on leaf spot of . , on fully submersed siliceous schist in high-mountain streams, and on the lower part and apothecial discs of on a twig. , on decaying wood, from moist soil with leaf litter, on a trunk of a living unknown hardwood tree species, and on dead twigs of unidentified plant.