Synthesis Of Pyridines Research Articles

CuO NPs catalyzed synthesis of quinolines, pyridines, and pyrroles via dehydrogenative coupling strategy

Copper oxide nanoparticles catalyzed efficient synthesis of quinolines, pyridines, and pyrroles via alcohol dehydrogenative coupling strategy are reported. Employing this catalytic system, various functionalized quinolines, pyridines, and pyrroles were synthesized efficiently from different amino alcohols with a diverse range of ketones. A number of control experiments were performed to shed light on the mechanism. This catalyst was recycled up to 6th run and notably, no significant loss was observed in its catalytic activity.

Ammonium metavanadate (NH4VO3): a highly efficient and eco-friendly catalyst for one-pot synthesis of pyridines and 1,4-dihydropyridines

In this study, we reported the ammonium metavanadate (NH4VO3) as an efficient, cost-effective, and mild catalyst for the synthesis of substituted pyridines via a one-pot pseudo four-component reaction. Furthermore, we investigated Hantzsch 1,4-dihydropyridines (1,4-DHPs) synthesis and oxidation of 1,4-DHPs to their corresponding pyridines. The present approach offers a rapid methodology for accessing various pyridines with broad functional group tolerance and good yields using NH4VO3 catalyst as a green catalyst.

1,2,3-Triazole-4(5)-amines – Convenient Synthetic Blocks for the Construction of Triazolo-Annulated Heterocycles

Aim. To analyze and summarize the synthetic potential of 1,2,3-triazole-4(5)-amines as efficient building blocks in the synthesis of triazolo-annulated pyridine, azine and azepine systems.Results and discussion. Original literature sources revealing the synthetic potential of 4(5)-amino functionalized 1,2,3-triazoles as convenient and available building blocks for the preparation of triazolo-annulated pyridines, azines and azepines were analyzed and systematized. Condensation of 1,2,3-triazole-4(5)-amines with methylene active compounds was shown to be a powerful tool for the synthesis of versatile triazolo[4,5-b]pyridines. In turn, the cyclocondensation based on 5-amino-1,2,3-triazole-4-carboxylic acids and their structurally modified derivatives was proven to be a general way for obtaining a number of triazolo[4,5-d]pyrimidine systems. Few representatives of triazolo-annulated pyridazines, 1,3-oxazines and 1,3-thiazines were synthesized by the intramolecular cyclization of the corresponding 4-aryl(carboxy-, aminomethyl)-5-amino-1,2,3-triazoles. The cyclocondensation involving 4,5-diamino-, 4-carbofunctionalized 5-amino-1,2,3-triazoles and 4-amino-5-thiocarboxamido-1,2,3-triazoles was successful for the construction of di-, oxa- and thiazepino-annulated triazoles.Conclusions. The analysis, systematization and summary of the literature regarding the synthetic potential of 1,2,3-triazole-4(5)-amines conclusively demonstrate that these structures are easily available and convenient molecular blocks for the construction of triazolo-annulated pyridine, azine and azepine systems that are important for synthetic and biomedical research.

Modeling of pyridine synthesis process in a coupled fluidized bed reactor

To obtain the optimal operating conditions of a coupled reactor for pyridine synthesis, reactor modeling process is carried out in this paper. During the modeling process, the flow hydrodynamics, heat transfer behavior, inter-phase mass transfer behavior and reaction kinetics were taken into consideration consequently. Further, a regression program based on least square method was proposed to regress the model parameters. The prediction results agreed well with the experimental results with an average deviation of 5.9%. Finally, by setting suitable aim function, the optimal operating conditions of the coupled reactor for pyridine synthesis were determined.

A Convenient Catalytic Method for the Synthesis of Pyridines with Henna and Pyrazole Moieties using Cooperative Vinylogous Anomeric‐Based Oxidation

AbstractIn this work, [Fe3O4@SiO2(CH2)3][DABCO‐H][C(CN)3]2 was prepared, identified by various analyses such as FT‐IR, EDX, SEM coupled EDX (SEM mapping), XRD, FE‐SEM, TEM, TGA, DTG, ICP and VSM and used as a nanomagnetic catalyst for the synthesis of henna‐based benzopyrazolo[3,4‐b]quinolindiones via cooperative vinylogous anomeric based oxidation under solvent‐free condition. Some of these products are new and reported for the first time.

Recent Advances in Synthesis of Multiply Arylated/Alkylated Pyridines.

Multiply aryl/alkyl-substituted pyridines are some of the untapped synthetic targets because of the challenge in regioselectively introducing less polar aryl/alkyl groups at the desired positions in the pyridine framework. Interestingly, the importance of this family of compounds has increased annually, particularly in biological and materials engineering applications. The syntheses of such pyridines have been extensively reported, but there is a lack of comprehensive review articles. Hence, this review discusses recent advances by grouping reaction patterns that generally deliver tri-, tetra-, and penta-aryl/alkyl pyridines.

Organocatalyzed Modular Synthesis of Polycyclic Dihydropyridines and Pyridines through Sulfamate Linchpin.

The cascade annulation between alkylidene malononitriles and cyclic sulfamidate imines has been controlled by leveraging the sulfamate functionality under organocatalysis, which allows selective access to polycyclic and densely functionalized dihydropyridines and pyridines in high yields. The protocol is scalable and shows broad substrate scope. The products were also engaged in the preparation of tetracyclic pyridopyrimidines, showcasing the synthetic versatility.

Synthesis of novel pyridine and pyrimidine thioglycoside phosphoramidates for the treatment of COVID-19 and influenza A viruses

A novel series of pyridine, cytosine, and uracil thioglycoside analogs (4a–i, 9a,b, and 13a,b, respectively) and their corresponding phosphoramidates (6a–I, 10a,b, and 14a,b, respectively) were synthesized and assessed for their antiviral inhibitory activities in a dual-pathogen screening protocol against SARS-CoV-2 and influenza A virus (IAV). MTT cytotoxicity (TC50) and plaque reduction assays were used to explore inhibition and cytotoxicity percentage values for H5N1 influenza virus strain and the half-maximal cytotoxic concentration (CC50) and inhibitory concentration (IC50) for SARS-CoV-2 virus. Most of the tested compounds demonstrated dose-dependent inhibition behavior. Both cytosine thioglycoside phosphoramidates 10a and 10b exhibited the most potent profiles with 83% and 86% inhibition at 0.25 µM concentration against H5N1 and IC50 values of 12.16 µM, 14.9 µM against SARS-CoV-2, respectively. Moreover, compounds 10a and 10b have been shown to have the highest selectivity index (SI) among all the tested compounds against SARS-CoV-2 with 28.2 and 26.9 values, respectively.

Synthesis, Characterization and Corrosion Inhibition of Novel Pyridine on Mild Steel in Hydrochloric Acid Environment

Corrosion inhibitions in corrosive solutions of hydrochloric acid for mild steel by chemical compound 3-acetyl-4-(4-bromophenyl)-6-2-oxo-2H-chromen-3-yl pyridine-2(1H)-one (ABCP), was conducted and the chemical structure was elucidated The Nuclear Magnetic Resonance (H-NMR) and Fourier Transform Infrared (FT-IR) spectroscopic techniques. The compound ABCP had been investigated at 25 ˚C via weight loss technique. The outcomes show that the ABCP displays great performances as an inhibitor for mild steel in 0.5 M hydrochloric acid. Inhibition efficiency increments with expanding of concentration and become 98.4% at the highest studied concentration. The studies have demonstrated a reverse association between corrosion rate (CR) and inhibition efficiency (IE percent), as IE increases while CR decreases with an increased concentration. In the presence of ABCP, inhibitory efficiency was up to 98.4% at 25°C in presence of ABCP (0.5 mM). IE drops notably at 65°C with an increased temperature. By means of FT -IR and NMR spectroscopy approaches and physical properties through melting point and Thin Layer Chromatography (TLC), the chemical structure of the tested inhibitor has been clarified.

Synthesis of Some Novel Pyridine, Sulfonamide, Coumarin and Thiophene Derivatives

Synthesis of Some Novel Pyridine, Sulfonamide, Coumarin and Thiophene Derivatives

Photocatalytic Synthesis of Trisubstituted Pyridines with Vinylene-Linked Covalent Organic Frameworks

Photocatalytic Synthesis of Trisubstituted Pyridines with Vinylene-Linked Covalent Organic Frameworks

Selective Synthesis of Pyridines and Pyrimidines Using Isopropene Derivatives

Key words annulation - pyridines - pyrimidines - isopropenes - cascade reaction

Self-sufficient whole-cell biocatalysis for 3-(aminomethyl) pyridine synthesis

3-(Aminomethyl) pyridine (3-AMP) is a versatile compound for the synthesis of pharmaceuticals, agricultural chemicals and numerous polymers. Efficient and mild biocatalytic synthesis is often an excellent supplement to traditional chemical synthesis methods. However, there has been no report of biocatalytic 3-AMP synthesis. In this paper, 3-AMP was synthesized for the first time by using biocatalysts co-expressing carboxylic acid reductase from Neurospora crassa (ncCAR) and ω-transaminase from Ochrobactrum anthropi (OATA) in one pot. In addition, the metabolic pathway was optimized by knocking out the transcriptional dual regulator arcA, which resulted in a 90% increase in the yield of 3-AMP. Furthermore, efficient self-sufficient whole-cell bioconversion was established by optimization, achieving 93% yield and a 40.6 mM (4.4 g/L) titer of 3-AMP without additional carbon sources. This whole-cell bioconversion system was also suitable for the high-efficiency biocatalytic synthesis of other aromatic or heterocyclic primary amines, such as benzylamine, 2-furfurylamine, 4-fluorobenzylamine, 2,4-difluorobenzylamine and 2-(aminomethyl) pyridine.Being entirely biocatalytic, our one-pot procedure provides considerable advantages in terms of economic, environmental and safety impacts over reported chemical methods.

5(4)-Aminopyrazoles as effective reagents in the synthesis of pyrazolo-annulated pyridines

5(4)-Aminopyrazoles as effective reagents in the synthesis of pyrazolo-annulated pyridines

Ethynyl-SF4-Pyridines: Reagents for SF4-Alkynylation to Carbonyl Compounds.

The trans-tetrafluoro-λ6-sulfanyl (SF4) unit is medicinally attractive because of its high electronegativity, lipophilicity, and unique hypervalent structure. The trans-SF4 unit can characteristically connect two independent molecules linearly. However, there is no example of the use of this unit for medicinal chemistry due to difficulties in synthesis. We report the first synthesis of (ethynyl-trans-tetrafluoro-λ6-sulfanyl)pyridines (t-ethynyl-SF4-pyridines) and their use as versatile reagents for the first direct SF4-alkynylation to carbonyl compounds. The addition reaction of t-ethynyl-SF4-pyridines to the carbonyl group in the presence of MeLi smoothly afforded pyridine-SF4-propargylic tertiary and secondary alcohols in high yields.

Novel Urea-Functionalized Magnetic Nanoparticles as a Heterogeneous Hydrogen Bonding Catalyst for the Synthesis of New 2-Hydroxy Pyridines

A novel urea-functionalized silica-coated magnetic nanoparticle namely Fe3O4@SiO2@UBL was described as a reusable and recoverable heterogeneous hydrogen bonding catalyst. For characterization of the catalyst, varied techniques including Fourier-transform infrared (FT‐IR) spectroscopy, energy dispersive X‐ray (EDX) analysis, elemental mapping analysis, thermo gravimetric analysis/differential thermal analysis (TGA/DTG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) were applied. Then, its catalytic performance was screened for the synthesis of new 2-hydroxy pyridine derivatives bearing sulfonate or sulfonamide moiety. Also, in a plausible mechanistic route, the stereoelectronic role of a cooperative vinylogous anomeric-based oxidation is suggested for the aromatization of targeted molecules.

Synthesis, solvatochromism and DFT study of pyridine substituted benzanthrone with ICT characteristics

We have explored the relation between the substituent and optical nonlinearity of pyridinepiperazine substituted benzanthrone dye. We report the synthesis of 3-(4-(pyridine-2-yl)piperazin-1-yl)-7H-benzo[de]anthracen-7-one (Pyridine-PBA). The molecular structure of the title dye was further confirmed by using FT-IR, 1H NMR, 13C NMR, and X-ray crystallographic techniques. The 3-substituted benzanthrone dye was examined for solvent dependent photophysical properties. The polarity plots indicate that hydrogen bonding interactions are influential in most of the solvents. Further analysis of Stokes’ shift data with multi parameter solvent polarity scale signifies that with an increase in solvent hydrogen bond donor ability a bathochromic shift is observed resulting in an increment in the dipole moment of the Pyridine-PBA dye on excitation. Computational results indicate that the electron excitation has some charge transfer characteristics. Furthermore, the calculated first static hyperpolarizability (β) and second hyperpolarizability (γ) values using range separated DFT methods fare better than the estimates for urea.

Uses of chalcone acetophenone to synthesis heterocyclic compounds with cytotoxic and c-Met kinase activities

ABSTRACT. The aim of present study was the uses of a series of α,β-unsaturated carbonyl compounds (chalcones), in the synthesis of pyridine, pyran, thiophene, thiazole, together with their uses in heterocyclic synthesis. The work has resulted in the synthesis of a variety of 2,5-dihydropyridine, hydrazide-hydrazone, thiophene derivatives, coumarin, pyran and thiazolo[4,5-d]thiazole derivatives. The antitumor activities of the newly synthesized products were carried out against three cancer cell lines namely MCF-7, NCI-H460 and SF-268 and normal human cell line WI38. In addition, the inhibitions of most of the synthesized compounds against c-Met kinase were studied and results showed that many compounds were of high inhibitions, and these are considered as promising anticancer agents. The results obtained encouraged further work in the future. 
 
 KEY WORDS: Chalcones, Heterocyclic, Pyridine, Pyran, Thiophene, Thiazole, Antitumor
 Bull. Chem. Soc. Ethiop. 2022, 36(1), 149-172. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i1.13

Synthesis and efficiency of new pyridine, chromene and thiazole containing compounds as antimicrobial and antioxidant agents

ABSTRACT. The versatile scaffold, N'-(2-cyanoacetyl)-2-hydroxybenzohydrazide (3) was utilized in the production of new pyridine, chromene and thiazole derivatives as antimicrobial and antioxidant agents. The synthetic strategy involves the treatment of precursor 3 with various arylidene-malononitrile and 3-aryl-2-cyanoacrylate compounds to furnish substituted pyridines 5 and 7. The interaction of 3 with salicylaldehyde and/or phenyl isothiocyanate followed by cyclization with chloroacetone produced the corresponding 2-imino-2H-chromene-3-carbohydrazide and (thiazol-2-ylidene-acetyl)-salicylic acid hydrazide compounds 8 and 9, respectively. The structural features of the synthesized compounds were confirmed by using spectroscopic methods such as (IR, 1H NMR, 13C NMR and MS). The new pyridine, chromene and thiazole products showed potent antioxidants and antimicrobial activities. The thiazole derivative 9 exhibited the highest anti-bacterial and antifungal activities against S. aureus (75.0%) and B. subtilis (73.9%) and C. albicans (66.6%). The combination between salicylic acid hydrazide and thiazole moieties in the hybrid 9 indicated the best antioxidant activity (87.9%).
 
 KEY WORDS: Salicylic hydrazide, Arylidene-malononitrile, Pyridine, Thiazole, Antioxidant
 
 Bull. Chem. Soc. Ethiop. 2022, 36(1), 137-148. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i1.12

Synthesis of Densely Substituted Pyridine Derivatives from 1-Methyl-1,3-(ar)enynes and Nitriles by a Formal [4+2] Cycloaddition Reaction.

An attractive method for assembling densely substituted pyridine derivatives from 1-methyl-1,3-(ar)enynes and nitriles via a formal [4+2] cycloaddition has been established. The well-balanced affinities of two alkali metal salts enable C(sp3)-H bond activation and excellent chemo- and regioselectivities. Experimental studies revealed that nitrile functions only as a partial nitrogen source for pyridine synthesis, and the addition of a metalated imine intermediate to an intramolecular alkyne is the rate-limiting step.