Synthesis and optimization of picolinamide derivatives as a novel class of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors

Applications of palladium-catalyzed C-N cross-coupling reactions in pharmaceutical compounds

C-N cross-coupling bond formation reactions have become valuable approaches to synthesizing anilines and their derivatives, known as important chemical compounds. Recent developments in this field have focused on versatile catalysts, simple operation methods, and green reaction conditions. This review article presents an overview of C-N cross-coupling reactions in pharmaceutical compound synthesis reports. Selected examples of N-arylation reactions of various nitrogen-based compounds and aryl halides are defined for preparing pharmaceutical molecules.

11β-Hydroxysteroid Dehydrogenase Type 1 as a Potential Treatment Target in Cardiovascular Diseases

Glucocorticoids (GCs) belong to the group of steroid hormones. Their representative in humans is cortisol. GCs are involved in most physiological processes of the body and play a significant role in important biological processes, including reproduction, growth, immune responses, metabolism, maintenance of water and electrolyte balance, functioning of the central nervous system and the cardiovascular system. The availability of cortisol to the glucocorticoid receptor is locally controlled by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Evidence of changes in intracellular GC metabolism in the pathogenesis of obesity, metabolic syndrome (MetS) and cardiovascular complications highlights the role of selective 11β-HSD1 inhibition in the pharmacotherapy of these diseases. This paper discusses the role of 11β-HSD1 in MetS and its cardiovascular complications and the importance of selective inhibition of 11β-HSD1.

Multi-Targeted Molecular Docking, Pharmacokinetics, and Drug-Likeness Evaluation of Okra-Derived Ligand Abscisic Acid Targeting Signaling Proteins Involved in the Development of Diabetes

Diabetes mellitus is a global threat affecting millions of people of different age groups. In recent years, the development of naturally derived anti-diabetic agents has gained popularity. Okra is a common vegetable containing important bioactive components such as abscisic acid (ABA). ABA, a phytohormone, has been shown to elicit potent anti-diabetic effects in mouse models. Keeping its anti-diabetic potential in mind, in silico study was performed to explore its role in inhibiting proteins relevant to diabetes mellitus- 11β-hydroxysteroid dehydrogenase (11β-HSD1), aldose reductase, glucokinase, glutamine-fructose-6-phosphate amidotransferase (GFAT), peroxisome proliferator-activated receptor-gamma (PPAR-gamma), and Sirtuin family of NAD(+)-dependent protein deacetylases 6 (SIRT6). A comparative study of the ABA-protein docked complex with already known inhibitors of these proteins relevant to diabetes was compared to explore the inhibitory potential. Calculation of molecular binding energy (ΔG), inhibition constant (pKi), and prediction of pharmacokinetics and pharmacodynamics properties were performed. The molecular docking investigation of ABA with 11-HSD1, GFAT, PPAR-gamma, and SIRT6 revealed considerably low binding energy (ΔG from −8.1 to −7.3 Kcal/mol) and predicted inhibition constant (pKi from 6.01 to 5.21 µM). The ADMET study revealed that ABA is a promising drug candidate without any hazardous effect following all current drug-likeness guidelines such as Lipinski, Ghose, Veber, Egan, and Muegge.

Progress in 11β-HSD1 inhibitors for the treatment of metabolic diseases: A comprehensive guide to their chemical structure diversity in drug development

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a key metabolic enzyme that catalyzing the intracellular conversion of inactive glucocorticoids to physiologically active ones. Work over the past decade has demonstrated the aberrant overexpression of 11β-HSD1 contributed to the pathophysiological process of metabolic diseases like obesity, type 2 diabetes mellitus, and metabolic syndromes. The inhibition of 11β-HSD1 represented an attractive therapeutic strategy for the treatment of metabolic diseases. Therefore, great efforts have been devoted to developing 11β-HSD1 inhibitors based on the diverse molecular scaffolds. This review focused on the structural features of the most important 11β-HSD1 inhibitors and categorized them into natural products derivatives and synthetic compounds. We also briefly discussed the optimization process, binding modes, structure-activity relationships (SAR) and biological evaluations of each inhibitor. Moreover, the challenges and directions for 11β-HSD1 inhibitors were discussed, which might provide some useful clues to guide the future discovery of novel 11β-HSD1 inhibitors.

Design, preparation and characterization of aerogel NiO–CuO–CoO/SiO2 nanocomposite as a reusable catalyst for C–N cross-coupling reaction

The aerogel nanocomposite produces using the sol–gel and supercritical drying method processes. The CO₂ supercritical drying (SCD) was taken as the most powerful process, ensuring the best properties of the product.

High Catalytic Activity of Pd Nanoparticles Synthesized from Green Alga Chlorella vulgaris in Buchwald-hartwig Synthesis of N-Aryl Piperazines

Background:

The N-aryl piperazines are an important component of many drug products used for the treatment of malaria, depression, anxiety and Parkinson diseases. Buchwald-Hartwig amination is the latest and well-known reaction for Pd catalyzed direct synthesis of N-aryl piperazine from aryl halides. Although several Pd-ligand systems have already been discovered for this conversion, Pd nanoparticles are recently being used for this useful coupling reaction due to their recyclability and durability. Metal nanoparticles show enhanced catalytic activity compared to their bulk counterparts due to increased surface area at the edges and corners. The use of green algal extract in place of chemical ligands makes this process more environment-friendly and cost-effective. In this research, Pd nanoparticles synthesized using green alga C. Vulgaris were utilized as an alternative approach for the coupling reaction during the preparation of N-aryl piperazines.

Methods:

Synthesized Pd nanoparticles from C. Vulgaris were characterized by FTIR, SEM and XRD techniques. The catalytic activity of the synthesized nanoparticles was monitored for the synthesis of N-aryl piperazines by Buchwald-Hartwig reaction. The synthesized N-aryl piperazines were characterized by NMR, FTIR and mass analysis.

Results:

A very good catalytic activity of the synthesized Pd nanoparticles from green alga Chlorella vulgaris extract was observed. The green alga not only reduces the size of the Pd metal to nanoparticles but also acts as a green ligand for reduction of Pd(II) to Pd(0) during nanoparticle synthesis. Using this Pd nanoparticles-green ligand system, several N-aryl piperazines were synthesized in good to excellent yields. Reaction conditions for better conversion were optimized. The comparative advantage of the catalytic system with recently published works on Buchwald-Hartwig C-N coupling reaction is given. Recyclability and durability of the catalyst were explored and the results were found to be promising. A plausible mechanism of Pd nanoparticle catalyzed reaction is also proposed.

Conclusion:

Catalytic activity of the Pd nanoparticle synthesized from Chlorella vulagris in the synthesis of N-aryl piperazines by Buchwald-Hartwig reaction is reported first time to the best of our knowledge and understanding. The green approach of Pd catalyst to facilitate the reaction and its environmental impact is the main characteristic of the process.

Impact of Adrenal Steroids on Regulation of Adipose Tissue

Corticosteroids are secreted by the adrenal glands and control the functions of adipose tissue via the activation of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR). In turn, adipocytes release a large variety of adipokines into the bloodstream, regulating the function of several organs and tissues, including the adrenal glands, hereby controlling corticosteroid production. In adipose tissue, the activation of the MR by glucocorticoids (GC) and aldosterone affects important processes such as adipocyte differentiation, oxidative stress, autophagic flux, adipokine expression as well as local production of GC through upregulation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Notably, the proinflammatory responses induced by the MR are counteracted by activation of the GR, whose activity inhibits the expression of inflammatory adipokines. Both GR and MR are deeply involved in adipogenesis and adipose expansion; hence pharmacological blockade of these two receptors has proven effective against adipose tissue dysfunction in experimental models of obesity and metabolic syndrome (MetS), suggesting a potential use for MR and GR antagonists in these clinical settings. Importantly, obesity and Cushing's syndrome (CS) share metabolic similarities and are characterized by high levels of circulating corticosteroids, which in turn are able to deeply affect adipose tissue. In addition, pharmacological approaches aimed at reducing aldosterone and GC levels, by means of the inhibition of CYP11B2 (aldosterone synthase) or 11β-HSD1, represent alternative strategies to counter the detrimental effects of excessive levels of corticosteroids, which are often observed in obesity and, more general, in MetS. © 2017 American Physiological Society. Compr Physiol 7:1425-1447, 2017.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.