Letters in Organic Chemistry - Volume 17, Issue 1, 2020

This review describes the synthesis and reactions of substituted pyrazolo[3,4-b] pyridines as a building block for the synthesis of polyfunctionalized heterocyclic compounds with pharmacological interest.

The combination of [γ-Fe2O3@HAp-SO3H] as a catalyst and ultrasonic effect catalyzed the synthesis of diverse derivatives of 2, 3-dihydroquinazolin-4(1H)-ones which is reported in this study. The products were synthesized via the one-pot three-component reaction of isatoic anhydride, amines and pyrazole carbaldehydes in water: EtOH catalyzed by recoverable [γ-Fe2O3@HAp-SO3H]. This paper conducted an investigation of the effect of various solvents, temperatures and catalysts on the reactions. Short reaction times, mild reaction conditions, simple work-up, the desired yields and the use of an appropriate catalyst are the advantages of this novel method. The new derivatives were validated by using FT-IR, 1HNMR, and 13CNMR. Moreover, the synthesized compounds were screened for their antimicrobial activity against bacterial strains.

The chemical investigation of the EtOAc extract of the fresh flowers of Juglans regia L. resulted in a new α-tetralonyl glucoside (1) and two known glucosides (2-3). The structure of the new compound was determined by extensive 1D and 2D NMR spectroscopic analysis and HRESIMS. The biological evaluation of the obtained glucosides showed that compound 1 and 3 displayed good antioxidant and antibacterial activities. These two compounds were identified as the main functional molecules in the fresh flowers of Juglans regia L.

The palladium-catalyzed Suzuki coupling reaction is one of the most efficient strategies for constructing a carbon-carbon bond. In recent years, bimetallic catalysts have become candidates for the Suzuki coupling reaction. In this work, Pd-Ni@2-Mercaptoethanol nanoparticles were synthesized for the Suzuki-Miyaura cross-coupling of arylboronic acids with aryl bromides, in the N,Ndimethylformamide/ water mixture catalyzed by Pd-Ni: A simple and efficient reaction performed in a solvent, without a ligand, and in open air. We found that the Suzuki-Miyaura reactions are remarkably fast (5 min), with high yields and the products are highly pure. The Pd-Ni@2-Mercaptoetanol nanoparticles have a narrow size distribution with a mean crystallite size of 10 nm. Radical scavenging activities of the complexes have been evaluated by using DPPH, DMPD+ and ABTS+ assays. IC50 values (μg/ml) of the complexes and standards on DPPH, DMPD+ and ABTS+ respectively following the sequences.

A new chalcone derivative, called as 1-(4-(benzylideneamino)phenyl)-3-(furan-2-yl)prop-2- en-1-one (I), was synthezised and characterized by spectral methods (infrared (IR) and proton and carbon- 13 nuclear magnetic resonance (1H- and 13C-NMR) spectroscopy). A computational study was performed by the density functional theory (DFT) method. Spectral data of compound I optimized by using 6-311G(d,p) and 6-311++G(d,p) basis sets were obtained by 6-311++G(d,p) basis set. The E-Z isomerism for newly synthesized chalcone derivative was investigated by considering four isomeric form, E/E, E/Z, Z/E and Z/Z. The results show that, as assumed and thus named, the chalcone derivative is in the E/E form. In addition, quantum chemical parameters were calculated by using DFT method with 6-311++G(d,p) basis set. Antioxidant activity of compound I was determined by the ferric reducing ability of plasma (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay methods. Compound I has low antioxidant activity.

Cancer is a second leading cause of death after heart attack, in developing as well as undeveloped countries. It is caused by unregulated growth and metastasis of the abnormal cancer cells. Cancer can be cured by radiation, immunotherapy and chemotherapy, among them; chemotherapy is a good treatment for cancer, in which chemotherapeutic drug is used. The anticancer activity of newly synthesized compounds (13a-j) was carried out on four different types of human cancer cell lines like MCF-7 (breast), A549 (lung), Colo-205 (colon) and A2780 (ovarian) by the MTT method, and compared to etoposide used as a positive control. Among them, compound 13g with electron-withdrawing (3,5-dinitro) group, exhibited more promising activity in all cell lines (MCF-7 = 0.10±0.076 μM, A549 = 0.17±0.039 μM, Colo-205= 0.13±0.022 μM and A2780 = 0.87±0.027μM). This compound may act as lead drug in cancer chemotherapy. In future, this compound can be examined for clinical studies.

An efficient protocol for the synthesis of symmetrical 3,3’-bis(indolyl)arylmethanes catalyzed by green and easily available ammonium iron(II) sulfate (Mohr’s salt) has been developed in “green” water solvent afforded in excellent yield.

Atazanavir is one of the most prescribed HIV-1 protease inhibitors approved by the FDA. It was the first protease inhibitor approved for once-a-day dosing to treat AIDS due to good oral bioavailability and favorable pharmacokinetic profile. This research aims to develop a new synthetic cost effective process for biaryl-hydrazine unit {tert-butyl 2-[4-(2-pyridinyl)benzyl]hydrazinecarboxylate} of atazanavir on a large scale. The synthesis involved palladium catalyzed Suzuki-Miyaura coupling of 2-chloropyridine and (4-cyanophenyl)boronic acid followed by DIBAL-H reduction of cyano group to aldehyde which is then treated with tert-butyl carbazate to furnish hydrazone subsequently in situ reduction with NaBH4. A large scale synthesis of biaryl-hydrazine unit of atazanavir was accomplished in three steps with 71% overall yield. We have developed a short and efficient synthesis of atazanavir key intermediate biaryl-hydrazine unit. The process does not require the usage of Grignard reagent, expensive catalyst, protection/deprotection of aldehyde moiety and catalytic hydrogenation.

A new Pt metal based nano-catalytic system was developed using organic-inorganic magnetic framework followed by the user-friendly protocol in good yield. XRD, FTIR, TEM, BET, ICP-OES and solid-state NMR techniques were used to characterize our developed catalytic system. The wellcharacterized ionic liquid bridged-silica supported magnetic Pt nanoparticles were utilized for the selective hydrogenation of carbon dioxide under high-pressure reaction condition (with and without ionic liquid medium). Most promising results were obtained while using the catalytic system (Pt-MagNP@ILSiO2) in 1,3-di (N, N-dimethylaminoethyl)-2-methylimidazolium nonafluorobutanesulfonate ([DAMI] [CF3CF2CF2CF2SO3]) task-specific ionic liquid medium. This TSIL not only provided a high degree of CO2 absorption during the reaction but also enhances the selectivity and the recyclability of the catalytic system up to 8 runs. No sign of Pt metal leaching was recorded during the recyclability test which confirmed the stability of this catalytic system under high-pressure reaction condition.