[Msim]CuCl3: as an efficient catalyst for the preparation of 5-amino-1H-pyrazole-4-carbonitriles by anomeric based oxidation

3-Methyl-1-sulfonic acid imidazolium trichlorido copper (II) {[Msim]CuCl3} was prepared and used as a new catalyst for the preparation of 5-amino-1H-pyrazole-4-carbonitriles. In this reaction, the pyrazole ring was formed by an anomeric and vinylogous anomeric effect in the structure of the product.

Substituted Pyrazoles and Their Heteroannulated Analogs-Recent Syntheses and Biological Activities

Pyrazoles are considered privileged scaffolds in medicinal chemistry. Previous reviews have discussed the importance of pyrazoles and their biological activities; however, few have dealt with the chemistry and the biology of heteroannulated derivatives. Therefore, we focused our attention on recent topics, up until 2020, for the synthesis of pyrazoles, their heteroannulated derivatives, and their applications as biologically active moieties. Moreover, we focused on traditional procedures used in the synthesis of pyrazoles.

Development of New Thiazole Complexes as Powerful Catalysts for Synthesis of Pyrazole-4-Carbonitrile Derivatives under Ultrasonic Irradiation Condition Supported by DFT Studies

In this study, we are interested in preparing Fe(III), Pd(II), and Cu(II) complexes from new thiazole derivatives. All syntheses were elaborately elucidated to estimate their molecular and structural formulae, which agreed with those of mononuclear complexes. The square-planer geometry of Pd(II) complex (MATYPd) was the starting point for its use as a heterocatalyst in preparing pyrazole-4-carbonitrile derivatives 4a-o using ultrasonic irradiation through a facile one-pot reaction. The simple operation, short-time reaction (20 min), and high efficiency (97%) were the special advantages of this protocol. Furthermore, this green synthesis strategy was advanced by examination of the reusability of the catalyst in four consecutive cycles without significant loss of catalytic activity. The new synthesis strategy presented remarkable advantages in terms of safety, simplicity, stability, mild conditions, short reaction time, excellent yields, and use of a H₂O solvent. This catalytic protocol was confirmed by the density functional theory (DFT) study, which reflected the specific characteristics of such a complex. Logical mechanisms have been suggested for the successfully exerted essential physical parameters that confirmed the superiority of the Pd(II) complex in the catalytic role. Optical band gap, electrophilicity, and electronegativity features, which are essential parameters for the catalytic behavior of the Pd(II) complex, are based mainly on the unsaturated valence shell of Pd(II).

Visible light triggered, catalyst free approach for the synthesis of thiazoles and imidazo[2,1-b]thiazoles in EtOH : H2O green medium

A catalyst free visible light assisted synthesis of thiazoles and imidazo[2,1-b]thiazoles in EtOH : H₂O green medium.

Graphene oxide–TiO2 composite: an efficient heterogeneous catalyst for the green synthesis of pyrazoles and pyridines

GO–TiO₂ has been found to be a highly efficient and recyclable heterogeneous catalyst for the synthesis of pyrazoles and pyridines in aqueous medium at room temperature.

Synthesis of pyrazole derivatives in the presence of a dioxomolybdenum complex supported on silica-coated magnetite nanoparticles as an efficient and easily recyclable catalyst

A dioxomolybdenum complex supported on functionalized Fe₃O₄ magnetite nanoparticles as a heterogeneous catalyst was synthesized, characterized and used in the synthesis pyrazole derivatives.

A convenient four-component one-pot strategy toward the synthesis of pyrazolo[3,4-d]pyrimidines

An efficient one-pot synthesis of pyrazolo[3,4-d]pyrimidine derivatives by the four-component condensation of hydrazines, methylenemalononitriles, aldehydes and alcohols has been developed via two different reaction pathways. The structures of target products were characterized by IR spectroscopy, NMR (¹H and ¹³C) spectroscopy and HRMS (ESI) spectrometry. The crystal structure of 4-ethoxy-6-(2-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine was determined by single crystal X-ray diffraction.

Catalytic applications of {[HMIM]C(NO2)3}: as a nano ionic liquid for the synthesis of pyrazole derivatives under green conditions and a mechanistic investigation with a new approach

1-Methylimidazolium trinitromethanide {[HMIM]C(NO₂)₃} as a nano structure ionic liquid was applied for the synthesis of pyrazole derivatives with high yields under mild and green conditions.

Meglumine catalyzed expeditious four-component domino protocol for synthesis of pyrazolopyranopyrimidines in aqueous medium

Meglumine has been found to be an efficient catalyst for the synthesis of structurally diverse tricyclic fused pyrazolopyranopyrimidines by one-pot, four-component reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes and barbituric acid in water.