Synthesis, benzodiazepine receptor binding and molecular modelling of isochromeno[4,3-c]pyrazol-5(1H)-one derivatives

The Fe3O4@apple seed starch core-shell structure decorated In(III): A green biocatalyst for the one-pot multicomponent synthesis of pyrazole-fused isocoumarins derivatives under solvent-free conditions

In current decades, the fabrication and design of magnetic biocatalysts have been advancing as green catalysts. Hence, in this paper, we use the apple seed starch to create indium(III) immobilized on Fe₃O₄@apple seed starch core-shell magnetic nanocatalyst (Fe₃O₄@apple seed starch-In(III)). The prepared catalyst was identified and evaluated with several analysis techniques. The application of this catalyst in the synthesis of isochromeno[4,3-c]pyrazole-5(1H)-one derivates under solvent-free conditions was a new approach with high efficiency. Due to the magnetic nature of the catalyst, the catalyst separation from the reaction medium is easy, and it is reusable for five runs without significant change in catalytic activity. The fabrication of this catalyst is based on green chemistry principles and is more economical and stable than other catalysts in the synthesis of pyrazole-fused isocoumarins heterocyclic compounds.

A facile and metal-free domino reaction of TsDAM and 2-alkenylarylaldehyde: An easy access to 8-hydroxy-2,8-dihydro indeno [2,1-c]pyrazoles

An efficient straightforward metal free domino approach was developed for the synthesis of various 8-hydroxy-2,8-dihydroindeno[2,1-c]pyrazoles via [3 + 2] cycloaddition of substituted alkenes and TsDAM (TosylDiAzoMethane). The salient features of this protocol include high efficiency, mild reaction conditions, greener solvent, metal-free reaction, scalability and broad substrate scope along with high regioselectivity and yields.

Bioactive pyrrole-based compounds with target selectivity

The discovery of novel synthetic compounds with drug-like properties is an ongoing challenge in medicinal chemistry. Natural products have inspired the synthesis of compounds for pharmaceutical application, most of which are based on N-heterocyclic motifs. Among these, the pyrrole ring is one of the most explored heterocycles in drug discovery programs for several therapeutic areas, confirmed by the high number of pyrrole-based drugs reaching the market. In the present review, we focused on pyrrole and its hetero-fused derivatives with anticancer, antimicrobial, and antiviral activities, reported in the literature between 2015 and 2019, for which a specific target was identified, being responsible for their biological activity. It emerges that the powerful pharmaceutical and pharmacological features provided by the pyrrole nucleus as pharmacophore unit of many drugs are still recognized by medicinal chemists.

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Pyrrole nucleus is one of the most explored heterocycle in drug discovery.

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Pyrrole derivatives exhibit antitumor, antimicrobial and antiviral activities.

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Targets involved in their biological activities were identified.

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SAR to underline their most important features were discussed.

Synthesis of Dihydropyrano[3,2-c]pyrazoles via Double Bond Migration and Ring-Closing Metathesis

Three types of pyrazole-fused heterobicycles, i.e., 1,5-, 1,7-, and 2,5-dihydropyrano[3,2-c]pyrazoles, were synthesized from 4-allyloxy-1H-pyrazoles. A sequence of the Claisen rearrangement of 4-allyloxy-1H-pyrazoles, ruthenium-hydride-catalyzed double bond migration, O-allylation, and ring-closing metathesis was employed in this study.

Anthranilamide-based 2-phenylcyclopropane-1-carboxamides, 1,1'-biphenyl-4-carboxamides and 1,1'-biphenyl-2-carboxamides: Synthesis biological evaluation and mechanism of action

Several anthranilamide-based 2-phenylcyclopropane-1-carboxamides 13a-f, 1,1'-biphenyl-4-carboxamides 14a-f and 1,1'-biphenyl-2-carboxamides 17a-f were obtained by a multistep procedure starting from the (1S,2S)-2-phenylcyclopropane-1-carbonyl chloride 11, the 1,1'-biphenyl-4-carbonyl chloride 12 or the 1,1'-biphenyl-2-carbonyl chloride 16 with the appropriate anthranilamide derivative 10a-f. Derivatives 13a-f, 14a-f and 17a-f showed antiproliferative activity against human leukemia K562 cells. Among these derivatives 13b, 14b and 17b exerted a particular cytotoxic effect on tumor cells. Derivative 17b showed a better antitumoral effect on K562 cells than 13b and 14b. Analyses performed to explore 17b mode of action revealed that it induced an arrest in G2/M phase of cell cycle which was consequent to DNA lesions as demonstrated by the increase in phospho-ATM and γH2AX, two known markers of DNA repair response system. The effect of 17b was also related to ROS generation, activation of JNK and induction of caspase-3 dependent apoptosis.

Synthesis and biofilm formation reduction of pyrazole-4-carboxamide derivatives in some Staphylococcus aureus strains

The ability of several N-phenyl-1H-pyrazole-4-carboxamide derivatives and other pyrazoles opportunely modified at the positions 3, 4 and 5, to reduce the formation of the biofilm in some Staphylococcus aureus strains (ATCC 29213, ATCC 25923 and ATCC 6538) were investigated. All the tested compounds were able, although to a different extent, to reduce the biofilm formation of the three bacterial strains considered. Among these, the 1-(2,5-dichlorophenyl)-5-methyl-N-phenyl-1H-pyrazole-4-carboxamide 14 resulted as the best inhibitor of biofilm formation showing an IC50 ranging from 2.3 to 32 μM, against all the three strains of S. aureus. Compound 14 also shows a good protective effect in vivo by improving the survival of wax moth larva (Galleria mellonella) infected with S. aureus ATCC 29213. These findings indicate that 14d is a potential lead compound for the development of new anti-virulence agents against S. aureus infections.

Synthesis and antiproliferative activity of new derivatives containing the polycyclic system 5,7:7,13-dimethanopyrazolo[3,4-b]pyrazolo[3',4':2,3]azepino[4,5-f]azocine

The reaction under reflux between 1-phenyl-3-R-5-methylaminopyrazoles and 2,5-hexanedione lead to 5,7:7,13-dimethanopyrazolo[3,4-b]pyrazolo[3',4':2,3]azepino[4,5-f]azocine derivatives 3b-g. These unusual molecules show the structural complexity of many biologically active natural products and are endowed with the chemical diversity that is required in drug discovery. The compounds 3b,e were reduced by hydrogen in the presence of Palladium on activated charcoal to give the dihydro derivatives 5b,e. Compounds 3b-f and 5b,e were selected by the NCI to evaluate their in vitro antiproliferative activity against 60 human cell lines derived from nine clinically isolated cancer types (leukaemia, lung, colon, melanoma, renal, ovarian, brain, breast, and prostate). The most active compound of this series, caused a block in G0-G1 phase of cell cycle. Analysis of pRb expression showed that this compound favours pRb dephosphorylation.

Non-classical transformation of benzendiazonium hydrogen sulfates. Access to 1,3-dimethylisochromeno[4,3-c]pyrazol-5(1H)-one, a potential benzodiazepine receptor ligand

The compound 2-((1,3-dimethyl-1H-pyrazol-5-yl)(methyl)carbamoyl)benzene-diazonium hydrogen sulfate (10) was reacted with copper sulfate and sodium chloride, in the presence of ascorbic acid as reducing agent, to afford a mixture of the chlorinated epimers 4′-chloro-2,2′,5′-trimethyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (18) and (19), the epimers 4′-hydroxy-2,2′,5′-trimethyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (20) and (21), and N-(1,3-dimethyl-1H-pyrazol-5-yl)benzamide (22). Under the foregoing conditions, diazonium salt 10 affords neither the 2-chloro-N-(1,3-dimethyl-1H-pyrazol-5-yl)-N-methylbenzamide (23) nor the tricyclic derivative 24, the classical products of the Sandmeyer and Pschorr reactions, respectively. Finally, by heating 20 at 210 °C the compound 1,3-dimethylisochromeno[4,3-c]pyrazol-5(1H)-one (24) was obtained. The transformation under the above conditions of 2-((4-chloro-3-methyl-1-phenyl-1H-pyrazol-5-yl)(methyl)carbamoyl)benzendiazonium hydrogen sulphate (11) afforded 4′,4′-dichloro-2,5′-dimethyl-2′-phenyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (29) as the sole reaction product.