Cobalt Nanoparticles Supported on Nitrogen-Doped Carbon: An Effective Non-Noble Metal Catalyst for the Upgrade of Biofuels

A new method has been developed for the deoxygenation of vanillin to produce 2-methoxy-4-methylphenol (MMP) as a promising liquid fuel over a heterogeneous non-noble metal catalyst. Cobalt nanoparticles supported on nitrogen-doped carbon (Co/N-C-600) exhibit high activity and stability for the deoxygenation of vanillin into MMP under mild conditions (150 °C, 10 bar H₂ ). Nearly quantitative MMP yield is obtained in isopropanol after 8 h at 150 °C and 10 bar H₂ pressure. According to the distribution of products with time, the deoxygenation of vanillin into MMP mainly proceeds through the hydrogenation of vanillin into vanillyl alcohol and the subsequent hydrogenolysis of vanillyl alcohol into MMP, of which the latter is the rate-determining step, owing to a much higher activation energy. Moreover, after being recycled several times, the loss of catalytic activity is negligible, which demonstrates that the Co/N-C-600 catalyst shows good resistance to deactivation.

Structure driven design of novel human ether-a-go-go-related-gene channel (hERG1) activators

One of the main culprits in modern drug discovery is apparent cardiotoxicity of many lead-candidates via inadvertent pharmacologic blockade of K⁺, Ca²⁺ and Na⁺ currents. Many drugs inadvertently block hERG1 leading to an acquired form of the Long QT syndrome and potentially lethal polymorphic ventricular tachycardia. An emerging strategy is to rely on interventions with a drug that may proactively activate hERG1 channels reducing cardiovascular risks. Small molecules-activators have a great potential for co-therapies where the risk of hERG-related QT prolongation is significant and rehabilitation of the drug is impractical. Although a number of hERG1 activators have been identified in the last decade, their binding sites, functional moieties responsible for channel activation and thus mechanism of action, have yet to be established. Here, we present a proof-of-principle study that combines de-novo drug design, molecular modeling, chemical synthesis with whole cell electrophysiology and Action Potential (AP) recordings in fetal mouse ventricular myocytes to establish basic chemical principles required for efficient activator of hERG1 channel. In order to minimize the likelihood that these molecules would also block the hERG1 channel they were computationally engineered to minimize interactions with known intra-cavitary drug binding sites. The combination of experimental and theoretical studies led to identification of functional elements (functional groups, flexibility) underlying efficiency of hERG1 activators targeting binding pocket located in the S4–S5 linker, as well as identified potential side-effects in this promising line of drugs, which was associated with multi-channel targeting of the developed drugs.

Synthesis, crystal structure and spectral properties of 2-[(1-Methyl-2-benzimidazolyl)azo]-p-cresol: an experimental and theoretical study

2-[(1-Methyl-2-benzimidazolyl)azo]-p-cresol (HL), containing phenolic-OH function and benzimidazole moiety has been synthesized and characterized. The chemical, electronic structure and photophysical properties have been studied by spectroscopic analysis abetted with DFT and TDDFT calculations. The change in electronic spectra of HL by titration with aq. NaOH is studied and well supported by TDDFT calculations. The structure is confirmed by single crystal X-ray study. In the unit cell, two HL molecules are H-bonded with H2O molecule and forms dimmeric structure. The molecule forms 2D-supramolecular structure by inter-molecular H-bonding and π-π interactions.

Structure-activity relationships of bisphenol A analogs at estrogen receptors (ERs): discovery of an ERα-selective antagonist

Our multi-template approach for drug discovery, focusing on protein targets with similar fold structures, has yielded lead compounds for various targets. We have also shown that a diphenylmethane skeleton can serve as a surrogate for a steroid skeleton. Here, on the basis of those ideas, we hypothesized that the diphenylmethane derivative bisphenol A (BPA) would bind to the ligand-binding domain of estrogen receptors (ERs) in a similar manner to estradiol and act as a steroid surrogate. To test this idea, we synthesized a series of BPA analogs and evaluated their structure-activity relationships, focusing on agonistic/antagonistic activities at ERs and ERα/ERβ subtype selectivity. Among the compounds examined, 18 was found to be a potent ERα-antagonist with high selectivity over ERβ and androgen receptor under our assay conditions. A computational docking study suggested that 18 would bind to the antagonistic conformation of ERα. ERα-selective antagonists, such as 18, are candidate agents for treatment of breast cancer.

Enantioselective Synthesis of (S)- and (R)-Tolterodine by Asymmetric Hydrogenation of a Coumarin Derivative Obtained by a Heck Reaction

An efficient and short enantioselective synthesis of (S)- and (R)-tolterodine was performed by asymmetric hydrogenation of a coumarin intermediate, easily obtained by a Heck reaction from inexpensive and commercially available starting materials.

New [LNiII2]+ Complexes Incorporating 2-Formyl or 2,6-Diformyl-4-methyl Phenol as Inhibitors of the Hydrolysis of the Ligand L3-: Ni···Ni Ferromagnetic Coupling and S = 2 Ground States

Reaction of the dinucleating ligand H3L (2-(2'-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine) with Ni(NO3)(2).6H2O produces the dimer of monomers [Ni(HL1)]2(NO3)(2).4H2O (1.4H2O) following the hydrolysis of H3L. If the reaction occurs in the presence of 2-formylphenol (Hfp) or 2,6-diformyl-4-methylphenol (Hdfp), this hydrolysis is prevented by incorporation of these co-ligands into the structure and stabilization of the new complexes [Ni2L(fp)(H2O)].3H2O (2.3H2O) and [Ni2L(dfp)].4.5H2O (3.4.5H2O), respectively. Complexes 2 and 3 may be considered to be structural models of the active site of urease, where coordination of the carbonyl ligand mimics binding of urea. In complex 2, coordination of terminal water reproduces the binding of this substrate of the enzyme to the active site. In both dinuclear complexes, the NiII ions are coupled ferromagnetically to yield S=2 ground states, whereas complex 1 exhibits weak intradimer antiferromagnetic exchange through hydrogen bonds. The magnetic data can be modeled by using the Van Vleck equation, incorporating intermolecular interactions, or by diagonalization of a spin Hamiltonian that includes single-ion anisotropy.

Rhodium-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to Coumarins: Asymmetric Synthesis of (R)-Tolterodine

[reaction: see text]. Rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to coumarins proceeded with high enantioselectivity in the presence of a rhodium catalyst (3 mol %) generated from Rh(acac)(C2H4)2 and (R)-Segphos to give the corresponding (R)-4-arylchroman-2-ones in over 99% ee. This asymmetric reaction was applied to the synthesis of (R)-tolterodine.

Design, synthesis and activity of novel derivatives of Oxybutynin and Tolterodine

Novel derivatives of Tolterodine (1) and Oxybutynin (2) have been designed using conformationally restricted azabicyclics as replacement for open-chain amines. The synthesis and structure-activity relationships are presented.

Enantioselective [4 + 2] cycloadditions of o-quinone methides: total synthesis of (+)-mimosifoliol and formal synthesis of (+)-tolterodine

The first example of an enantioselective cycloaddition of an o-quinone methide (o-QM) with a chiral enol ether is described along with the total synthesis of (+)-mimosifoliol and the formal synthesis of (+)-tolterodine. These syntheses exemplify a three-component, one-pot benzopyran approach for the construction of chiral benzylic junctions. Cycloadditions of various enol ethers and o-QMs are examined, and diastereoselectivities >95% are obtained with trans-2-phenyl-1-cyclohexanol and 2,2-diphenylcyclopentanol vinyl ethers.

An improved method for the rapid preparation of 2-amino-4,4a-dihydro-4a,7-dimethyl-3H-phenoxazine-3-one, a novel antitumor agent

A simple and rapid preparation method for a novel antitumor agent, 2-amino-4,4a-dihydro-4a,7-dimethyl-3H-phenoxazine-3-one (Phx) was described. The procedure included (1) the reaction of bovine hemolysates with 2-amino-5-methylphenol, (2) one-shot denaturation of hemoglobin and proteins by methanol, and removal of the denatured hemoglobin and proteins, (3) concentration of the reaction products, and (4) purification by a Sephadex column. These procedures yielded Phx in 34% yield.