Project description:Two series of fused tetrahydro-β-carboline hydantoin and tetrahydro-β-carboline thiohydantoin derivatives with a pendant 2,4-dimethoxyphenyl at position 5 were synthesized, and chiral carbons at positions 5 and 11a swing from R,R to R,S, S,R, and S,S. The prepared analogues were evaluated for their capacity to inhibit phosphodiesterase 5 (PDE5) isozyme. The R absolute configuration of C-5 in the β-carboline hydantoin derivatives was found to be essential for the PDE5 inhibition. Chiral carbon derived from amino acid even if of the S configuration (L-tryptophan) may lead to equiactive or more active isomers than those derived from amino acid with the R configuration (D-tryptophan). This expands the horizon from which efficient PDE5 inhibitors can be derived and may offer an economic advantage. The thiohydantoin derivatives were less active than their hydantoin congeners.
Project description:This article provides an overview of a deep eutectic mixture based on the application of lithium nitrate (V) and acetamide as an electrolyte in a carbon-based electrochemical capacitor. This type of electrolyte is intended to be applied in devices designed for operation under critical conditions (e. g., extreme temperatures). In contrast to water- and common organic-based formulations, the proposed electrolyte ensures good device performance at 100 °C. To describe the chemistry of the proposed mixture, infrared and Raman spectroscopy, differential scanning calorimetry, and gas chromatography with mass spectrometry were used. Electrochemical analysis includes the verification of system ageing, self-discharge monitoring, leakage current measuring, and fundamental testing related to determining the specific capacitance or maximum voltage. Additionally, comprehensive analysis of the lithium nitrate salt and organic solvent addition to the operating system was carried out, including the replacement of lithium ions with sodium or potassium.
Project description:Dairy mastitis is a disease of dairy cattle caused by a variety of pathogenic microorganisms which has biought huge economic losses aused huge economic losses to the world. In this paper, Harmine derivatives and tetrahydro-β-carboline derivatives synthesized by the splice method are shown to have a good inhibitory effect on the pathogenic bacteria of dairy mastitis. The results of a bacteriostatic test on pathogenic bacteria of dairy cow mastitis (S. dysgalactiae, S. pyogenes, B. subtilis and P. vulgaris) showed that compound 7l had the best bacteriostatic effect on Streptococcus dysgalactiae, with a mic value of 43.7 μ g/mL. When the concentration of 7l was 1 × MIC and 2 × MIC, it had a significant inhibitory effect on Streptococcus dysgalactiae, and there was almost no growth of Streptococcus dysgalactiae at 4 × MIC. The binding properties of target compound 7l to amine oxidase [flavin-containing] A protein were simulated by the molecular docking technique. The ligand 7l achieved strong binding with the receptor through three hydrogen bonds. The hydrogen bonds were amino acid residues thr-52, arg-51 and ser-24, which are the main force for the compound to bind to active sites.
Project description:An enhanced, sustainable, and efficient method for synthesizing tacrine, achieving a 98% yield, has been developed by replacing volatile organic compounds with more eco-friendly solvents such as deep eutectic solvent (DESs). The optimized protocol scales easily to 3 g of substrate without yield loss and extends successfully to tacrine derivatives with reduced hepatotoxicity. Particularly notable is the synthesis of novel triazole-based derivatives, yielding 90-95%, by integrating an in situ preparation of aryl azides in DESs with N-propargyl-substituted tacrine derivatives. Quantitative metrics validate the green aspects of the reported drug development processes.
Project description:Starting from tadalafil as a template, a series of functionalized tetrahydro-β-carboline derivatives have been prepared and identified as novel potent and selective PDE5 inhibitors. Replacing the 3,4-methylenedioxyphenyl at position 6 of tadalafil, together with elongation of the N2-methyl substituent and manipulation of the stereochemical aspects of the two chiral carbons led to the identification of compound XXI, a highly potent PDE5 inhibitor (IC(50) = 3 nM). Compound XXI was also highly selective for PDE5 versus PDE3B, PDE4B, and PDE11A, with a selectivity index of 52 and 235 towards PDE5 rather than PDE11 with both cAMP and cGMP as substrate, respectively.
Project description:An efficient and novel protocol was developed for a Cu-catalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [CuI or CuII species] loading up to 5 mol% and K2 CO3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70-96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E-factor as low as 5.76.
Project description:New derivatives based upon the tetrahydro-β-carboline-hydantoin and tetrahydro-β-carboline-piperazinedione scaffolds were synthesized. All compounds were evaluated for their ability to inhibit PDE5 in vitro, and numerous compounds with IC(50) values in the low nanomolar range were identified including compounds derived from l-tryptophan. Compounds with high potency versus PDE5 were then evaluated for inhibitory activity against other PDEs to assess isozyme selectivity. Compound 5R,11aS-5-(3,4-dichlorophenyl)-2-ethyl-5,6,11,11a-tetrahydro-1H-imidazo[1',5':1,6]pyrido[3,4-b]indole-1,3(2H)dione 14 showed a selectivity index of >200 for cGMP hydrolysis by PDE5 versus PDE11. Meanwhile, 6R,12aR-6-(2,4-dichlorophenyl)-2-ethyl-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4dione 45 demonstrated strong potency for inhibition of PDE11 with an IC(50) value of 11 nM, representing the most potent PDE11 inhibitor thus far reported. Docking experiments differentiated between active and inactive analogues and revealing the conformational, steric, and lipophilic necessities for potent PDE5 inhibition. Many derivatives, including potent PDE5 inhibitors, were able to inhibit the growth of the MDA-MB-231 breast tumor cell line with low micromolar potency.
Project description:Deep eutectic solvents (DESs) are eutectic mixtures of salts and hydrogen bond donors with melting points low enough to be used as solvents. DESs have proved to be a good alternative to traditional organic solvents and ionic liquids (ILs) in many biocatalytic processes. Apart from the benign characteristics similar to those of ILs (e.g., low volatility, low inflammability and low melting point), DESs have their unique merits of easy preparation and low cost owing to their renewable and available raw materials. To better apply such solvents in green and sustainable chemistry, this review firstly describes some basic properties, mainly the toxicity and biodegradability of DESs. Secondly, it presents several valuable applications of DES as solvent/co-solvent in biocatalytic reactions, such as lipase-catalyzed transesterification and ester hydrolysis reactions. The roles, serving as extractive reagent for an enzymatic product and pretreatment solvent of enzymatic biomass hydrolysis, are also discussed. Further understanding how DESs affect biocatalytic reaction will facilitate the design of novel solvents and contribute to the discovery of new reactions in these solvents.
Project description:Antagonism of somatostatin subtype receptor 3 (sstr3) has emerged as a potential treatment of Type 2 diabetes. Unfortunately, the development of our first preclinical candidate, MK-4256, was discontinued due to a dose-dependent QTc (QT interval corrected for heart rate) prolongation observed in a conscious cardiovascular (CV) dog model. As the fate of the entire program rested on resolving this issue, it was imperative to determine whether the observed QTc prolongation was associated with hERG channel (the protein encoded by the human Ether-à-go-go-Related Gene) binding or was mechanism-based as a result of antagonizing sstr3. We investigated a structural series containing carboxylic acids to reduce the putative hERG off-target activity. A key tool compound, 3A, was identified from this SAR effort. As a potent sstr3 antagonist, 3A was shown to reduce glucose excursion in a mouse oGTT assay. Consistent with its minimal hERG activity from in vitro assays, 3A elicited little to no effect in an anesthetized, vagus-intact CV dog model at high plasma drug levels. These results afforded the critical conclusion that sstr3 antagonism is not responsible for the QTc effects and therefore cleared a path for the program to progress.
Project description:Tadalafil is a clinically approved phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction and pulmonary arterial hypertension. It contains two chiral carbons, and the marketed isomer is the 6R, 12aR isomer with a methyl substituent on the terminal nitrogen of the piperazinedione ring. In this report, tadalafil analogues with an extended hydrophilic side chain on the piperazine nitrogen were designed to interact with particular hydrophilic residues in the binding pocket. This leads to analogues with moderate inhibitory activity on phosphodiesterase-5, even for isomers in which chiral carbons are of the S configuration.