A green and efficient protocol for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives via a one-pot, four component reaction by grinding method

Recent Applications of the Multicomponent Synthesis for Bioactive Pyrazole Derivatives

Pyrazole and its derivatives are considered a privileged N-heterocycle with immense therapeutic potential. Over the last few decades, the pot, atom, and step economy (PASE) synthesis of pyrazole derivatives by multicomponent reactions (MCRs) has gained increasing popularity in pharmaceutical and medicinal chemistry. The present review summarizes the recent developments of multicomponent reactions for the synthesis of biologically active molecules containing the pyrazole moiety. Particularly, it covers the articles published from 2015 to date related to antibacterial, anticancer, antifungal, antioxidant, α-glucosidase and α-amylase inhibitory, anti-inflammatory, antimycobacterial, antimalarial, and miscellaneous activities of pyrazole derivatives obtained exclusively via an MCR. The reported analytical and activity data, plausible synthetic mechanisms, and molecular docking simulations are organized in concise tables, schemes, and figures to facilitate comparison and underscore the key points of this review. We hope that this review will be helpful in the quest for developing more biologically active molecules and marketed drugs containing the pyrazole moiety.

Acetylenic Esters in Organic Synthesis

Activated acetylenic substrates such as acetylenic esters and alkyl propiolates are very important in organic synthesis. Due to their electron deficiency, these compounds are widely used in combinatorial and multicomponent reactions, enabling the synthesis of a large variety of novel compounds. In addition, these substrates are powerful Michael acceptors and convenient dienophiles and dipolarophiles in Diels–Alder and 1,3-dipolar cycloaddition reactions. The addition of different nucleophiles, primarily phosphorus, nitrogen or sulfur, to the triple bonds of these substrates produces key intermediates, such as Tebby and Huisgen zwitterions, which can lead to designing pathways toward the generation of spirocyclic and polycyclic compounds. This account highlights recent studies on the chemistry of acetylenic esters and their applications in organic synthesis.

1 Introduction

2 Synthesis of Acyclic and Monocyclic Compounds

3 Synthesis of Spirocyclic Compounds

4 Synthesis of Polycyclic Compounds

5 Conclusion

Dry Grinding Synthesis and Docking Study of Cyclopentanone-Sulfur Containing Compounds with Anti-Proliferative Activity for HepG-2 and A-549 Cancer Cell Lines

BACKGROUND

The dry grinding method is a green technique for efficient organic synthesis with numerous advantages, such as: mild reaction conditions, environmental acceptability, simple segregation and refinement as well as the elevated selectivity and efficiency.

OBJECTIVE

The aim of the present work is to design and synthesize of cyclopentylidene-hydrazino)-thiazole derivatives using dry grinding condition to investigate their antitumor activity aganist two cell lines namely, HepG-2 and A-549.

METHODS

In this context, we synthesized series of thiazole incorporated cyclopentane through hydrazone-group and 2-cyclopentylidenehydrazine-1-carbimidic-2-ethoxy-N-aryl-2-oxoacetohydrazonic thioanhydride under dry grinding within minutes and excellent to good yield.

RESULTS

All spectral data confirmed the proposed structures. The molecular docking studies have been performed using Macrophage Migration Inhibitory Factor (Pdb: 4k9g) and Lysozyme C (Pdb: 2f4a), the overexpressed proteins in human liver cancer cell (HepG-2) and lung cancer cell lines (A-549), respectively, in addition to the antitumor activity investigations contra the two types of tumor cells.

CONCLUSION

Two derivatives 9b and 9d showed the highest antitumor activity against the two cell lines HepG-2 and A-549. Also, docking results revealed high energy score ranging from -7.1590 to -5.9364 Kcal/mol with Macrophage Migration Inhibitory Factor (Pdb: 4k9g) which is more than the energy score = -4.118 Kcal/mol of co-crystallized ligand. Moreover, the tested derivatives showed energy score varies from -6.0802 to -4.5503 Kcal/mol against Lysozyme C (Pdb: 2f4a).

One-pot Synthesis of Pyrano[2,3-c]pyrazole Derivatives via Multicomponent Reactions (MCRs) and their Applications in Medicinal Chemistry

Background:

Many pyrano[2,3-c]pyrazole derivatives display diverse biological activities and some of them are known as anticancer, analgesic, anticonvulsant, antimicrobial, anti-inflammatory, and anti-malarial agents. In recent years, easy convergent, multicomponent reactions (MCRs) have been adopted to make highly functionalizedpyrano[2,3-c]pyrazole derivatives of biological interest. The synthesis of 1,4-dihydropyrano[2,3-c]pyrazole (1,4-DHPP, 2), 2,4-dihydropyrano[2,3-c]pyrazole (2,4-DHPP, 3), 4-hydroxypyrano[2,3-c]pyrazole (4-HPP, 4) derivatives, 1,4,4-substitied pyranopyrazole (SPP, 5) were reported via two-, three-, four- and five-component reactions (MCRs).

Methods:

This review article compiles the preparation of pyrano[2,3-c]pyrazole derivatives, and it highlights the applications of various pyrano[2,3-c]pyrazole derivatives in medicinal chemistry.

Results:

Varieties of pyrano[2,3-c]pyrazole derivatives were achieved via “One-pot” multicomponent reactions (MCRs). Different reaction conditions in the presence of a catalyst or without catalysts were adapted to prepare the pyrano[2,3-c]pyrazole derivatives.

Conclusion:

Biologically active pyrano[2,3-c]pyrazole derivatives were prepared and used in drug discovery research.

[18-C-6H3O+]: an in-situ generated macrocyclic complex and an efficient, novel catalyst for synthesis of pyrano[2,3-c]pyrazole derivatives

Synthesis of small aromatic heterocycles is of greater importance in the organic chemistry due to their vibrant applications in pharmaceuticals, agrochemicals and veterinary products. Pyranopyrazoles are one such class of heterocycles associated with numerous applications. Hence herein we report a multicomponent crown ether catalyzed, ultrasound irradiated methodology to make different functionalized pyranopyrazoles in a single step. This technique involves the in-situ generation of [18-C-6H₃O⁺][OH⁻] complex, which in turn activates the aromatic aldehyde and aids in the facile nucleophilic addition.

Synthesis of N,N'-bis(1,5-dimethyl-2-phenyl-1,2-dihydro-3-oxopyrazol-4-yl) sebacamide that ameliorate osteoarthritis symptoms and improve bone marrow matrix structure and cartilage alterations induced by monoiodoacetate in the rat model: "Suggested potent anti-inflammatory agent against COVID-19"

To assess the chondroprotective effect and influence of N,N′-bis(1,5-dimethyl-2-phenyl-1,2-dihydro-3-oxopyrazol-4-yl) sebacamide (dpdo) that was synthesized through the reaction of phenazone with sebacoyl chloride and screened for its biological activity especially as anti-arthritic and anti-inflammatory agent in a monoiodoacetate (MA)-induced experimental osteoarthritis (OA) model. Thirty male albino rats weighing “190–200 g” were divided randomly into three groups (10 each): control, MA-induced OA, and MA-induced OA + dpdo. In MA-induced OA rat, the tumor necrosis factor alpha, interleukin 6, C-reactive protein, rheumatoid factors, reactive oxygen species, as well as all the mitochondrial markers such as mitochondria membrane potential, swelling mitochondria, cytochrome c oxidase (complex IV), and serum oxidative/antioxidant status (malondialdehyde level and activities of myeloperoxidase and xanthine oxidase) are elevated. Also, the activity of succinate dehydrogenase (complex II), levels of ATP, the level of glutathione (GSH), and thiol were markedly diminished in the MA-induced OA group compared to the normal control rats. These findings showed that mitochondrial function is associated with OA pathophysiological alterations and high gene expressions of (IL-6, TNF-a, and IL-1b) and suggests a promising use of dpdo as potential ameliorative agents in the animal model of OA and could act as anti-inflammatory agent in case of severe infection with COVID-19. It is clearly appeared in improving the bone cortex and bone marrow in the treated group with the novel compound in histological and transmission electron microscopic sections which is a very important issue today in fighting severe infections that have significant effects on the blood indices and declining of blood corpuscles like COVID-19, in addition to declining the genotoxicity and inflammation induced by MA in male rats. The novel synthesized compound was highly effective in improving all the above mentioned parameters.

Synthesis and Antibacterial Screening of Some Pyrazole Derivatives Catalyzed by Cetyltrimethylammoniumbromide (CTAB)

AIMS

In this article, we have developed an eco-friendly one-pot multi-component reaction methodology employed for the green synthesis of functionalized pyrazole derivatives viz cyclo-condensation of aromatic aldehydes, ethyl acetoacetate and phenyl hydrazine and/or hydrazine hydrate in the presence of cetyltrimethylammoniumbromide (CTAB) at 90°C temperature in an aqueous medium.

MATERIALS AND METHODS

In the present protocol, we developed a green method for the synthesis of functionalized pyrazole derivatives through one-pot, multi-component cyclo-condensation of aromatic aldehydes, phenyl hydrazine or hydrazine hydrate and ethyl acetoacetate using cetyltrimethylammoniumbromide (CTAB) as a catalyst in water as a solvent. Our methodology confers advantages such as short reaction time, atom economy, purification of the product without using column chromatographic and hazardous solvent. The reaction is being catalyzed by cetyltrimethylammoniumbromide (CTAB) and thus, products are formed under the green reaction conditions.

RESULTS AND DISCUSSION

Initially, the reaction of benzaldehyde and phenylhydrazine with ethyl acetoacetate was carried out in water at room temperature in the absence of the catalyst; no product was obtained after 24 h (Table 1 entry 1). When the reaction was carried out using L-proline as a catalyst in ethanol at 70°C, the yield of the product was 20%.

CONCLUSION

This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. We consider that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in the future. In conclusion, we have developed successfully a green and efficient one-pot multi-component methodology for the synthesis of substituted pyrazoles using CTAB as a catalyst in water as a solvent with excellent yields. Purifications of compounds were achieved without the use of traditional chromatographic procedures. This methodology has advantages of operational simplicity, clean reaction profiles and relatively broad scope, which make it more attractive for the diversity oriented synthesis of these heterocyclic libraries. In this methodology, we suggest a further alternative possibility for the formation of substituted pyrazoles. The compound 7h can be used as an anticancer drug in the pharma industry.

SCMNPs@Uridine/Zn: An efficient and reusable heterogeneous nanocatalyst for the rapid one-pot synthesis of tricyclic fused pyrazolopyranopyrimidine and 3-methyl carboxylate substituted pyrano[2,3-c]pyrazole derivatives under solvent-free conditions

SCMNPs@Uridine/Zn is utilized as an environmental-friendly and efficient heterogeneous nanocatalyst for two one-pot four-component condensation reactions, containing hydrazine hydrate, arylaldehyde, ethyl acetoacetate, and barbituric acid to yield tricyclic fused pyrazolopyranopyrimidine derivatives (5a-q), and hydrazine hydrate, arylaldehyde, malononitrile, and dimethyl acetylenedicarboxylate/diethyl acetylenedicarboxylate to yield 3-methyl carboxylate substituted pyrano[2,3-c]pyrazole derivatives (8a-y) under solvent-free conditions with high to excellent yields. The main advantages of this process are easy work-up, short reaction times, no chromatographic purifications, and recyclability of the catalyst for a minimum of six runs without any significant decrease in yields of the products. Also, the prepared catalyst SCMNPs@Uridine/Zn was synthesized and fully characterized by various techniques including Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Raman spectroscopy.

Novel Anticancer Fused Pyrazole Derivatives as EGFR and VEGFR-2 Dual TK Inhibitors

EGFR and VEGFR-2 represent promising targets for cancer treatment as they are very important in tumor development as well as in angiogenesis and metastasis. In this work, 6-amino-4-(2-bromophenyl)-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile 1 and (E)-4-(2-Bromobenzylidene)-5-methyl-2,4-dihydro-3H-pyrazol-3-one 11 were selected as starting materials to synthesize different fused pyrazole derivatives; dihydropyrano[2,3-c]pyrazole 1, 2, 7–9, and 15, pyrazolo[4′,3′:5,6]pyrano[2,3-d]pyrimidine 3–6, pyrazolo[3,4-d]pyrimidine 12 and 13, and pyrazolo[3,4-c]pyrazole 14 derivatives were synthesized to evaluate their anticancer activity against HEPG2 human cancer cell lines compared to erlotinib and sorafenib as reference drugs. Seven compounds 1, 2, 4, 8, 11, 12, and 15 showed nearly 10 fold higher activity than erlotinib (10.6 μM) with IC₅₀ ranging from 0.31 to 0.71 μM. In vitro EGFR and VEGFR-2 inhibitory activity were performed for the synthesized compounds, and the results identified compound 3 as the most potent EGFR inhibitor (IC₅₀ = 0.06 μM) and compound 9 as the most potent VEGFR-2 inhibitor (IC₅₀ = 0.22 μM). Moreover, compounds 9 and 12 revealed potent dual EGFR and VEGFR-2 inhibition, and these results were supported by docking studies of these two compounds within the active sites of both enzymes.

Green Fabrication of Cobalt NPs using Aqueous Extract of Antioxidant Rich Zingiber and Their Catalytic Applications for the Synthesis of Pyrano[2,3-c]pyrazoles

AIM AND OBJECTIVE

In this study, biological synthesis of cobalt nanoparticles was developed in the presence of ginger extract as the reducing and capping agent through the simple and convenient co-precipitation method.

MATERIALS AND METHODS

The as-synthesized cobalt nanoparticles were characterized by X-ray diffraction (XRD), scanning Electron Microscopy (SEM), spectra energy dispersive analysis of Xray (EDS), Fourier transform infrared (FT-IR), and vibrating sample magnetometer (VSM) techniques. According to the vibrating sample magnetometer, cobalt nanoparticles show paramagnetic behaviour at room temperature. Furthermore, the effect of ginger extract concentration on the UV-Vis absorbance of Co nanoparticles was investigated. Based on the UVVis absorbance spectra, increasing ginger extract concentration causes particle size to decrease. In addition, the catalytic performance of the synthesized cobalt nanoparticles was investigated in the preparation of pyrano[2,3-c]pyrazoles via one-pot four-component reactions of aryl aldehydes, hydrazine hydrate, malononitrile and diethyl acetylenedicarboxylate.

RESULT AND CONCLUSION

The prepared pyrano[2,3-c]pyrazole derivatives were obtained in high yields within short reaction times and the nanocatalyst was easily separated using an external magnet and reused for several times with no significant loss of its activity.

I2-Catalyzed Oxidative Cross-Coupling Reaction of Methyl Ketones and 2-(2-Aminophenyl) Benzimidazole: Facile Access to Benzimidazo[1,2-c]quinazoline

A general and efficient iodine-catalyzed metal-free oxidative cross-coupling reaction of methyl ketones with 2-(1H-benzo[d]imidazol-2-yl)aniline has been established. This is a new synthetic strategy for the synthesis of benzimidazo[1,2-c]quinazoline derivatives involving C(sp³)-H oxidation, condensation, and cyclization processes.

Iodine-mediated C–N and C–S bond formation: regioselective synthesis of benzo[4,5]imidazo[2,1-b]thiazoles

The regioselective synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives via amination (C–N) and intramolecular cyclization (C–S) reactions in the presence of molecular iodine has been reported. This method is base and metal free and features inexpensive catalysts, with a simple procedure and a short reaction time.

Review: biologically active pyrazole derivatives

Nitrogen-containing heterocyclic compounds and their derivatives have historically been invaluable as a source of therapeutic agents.

A green and clean pathway: one pot, multicomponent, and visible light assisted synthesis of pyrano[2,3-c]pyrazoles under catalyst-free and solvent-free conditions

Visible light mediated, an eco-friendlier synthetic protocol for dihydropyrano[2,3-c]pyrazoles via catalyst-free and solvent-free conditions at room temperature.

A one-pot sequential five-component domino reaction for the expedient synthesis of polysubstituted pyrroles

A new protocol towards the synthesis of polysubstituted pyrroles via enaminone from one-pot five-component reactions under catalyst free conditions.