Synthesis, crystal structure and Hirshfeld surface analysis of dimethyl 3-(3-bromophenyl)-6-methyl-7-oxo-3,5,6,7-tetrahydropyrazolo[1,2-a]pyrazole-1,2-dicarboxylate

The title compound, C17H17BrN2O5, resulted from the 1,3-dipolar cycloaddition reaction between dimethyl acetylenedicarboxylate and (3-bromobenzylidene)-4-methyl-5-oxopyrazolidin-2-ium-1-ide in CHCl3. The dihedral angle between the pyrazole rings (all atoms) is 32.91 (10)°; the oxo-pyrazole ring displays an envelope conformation whereas the other pyrazole ring adopts a twisted conformation. The bromophenyl ring subtends a dihedral angle of 88.95 (9)° with the mean plane of its attached pyrazole ring. In the crystal, the molecules are linked by C—H...O hydrogen bonds and aromatic π–π interactions with an inter-centroid distance of 3.8369 (10) Å. The Hirshfeld surface analysis and fingerprint plots reveal that the molecular packing is governed by H...H (37.1%), O...H/H...O (31.3%), Br...H/H...Br (13.5%) and C...H/H...C (10.6%) contacts. The energy framework indicates that dispersion energy is the major contributor to the molecular packing.

Indazole and its derivatives in cardiovascular diseases: Overview, current scenario and future perspectives

: Indazoles are a class of heterocyclic compounds with a bicyclic ring structure composed of a pyrazole ring and a benzene ring. Indazole-containing compounds with various functional groups have important pharmacological activities and can be used as structural motifs in designing novel drug molecules. Some of the indazole-containing molecules are approved by FDA and are already in the market. However, very few drugs with indazole rings have been developed against cardiovascular diseases. This review aims to summarize the structural and pharmacological functions of indazole derivatives which have shown efficacy against cardiovascular pathologies in experimental settings.

Novel Dual Acting Antimalarial Antileishmanial Agents Derived from Pyrazole Moiety

Malaria and leishmaniasis are two highly detrimental parasitic diseases with a global impact. Attempts to eradicate malaria and control leishmaniasis are generally unsuccessful due to the rapidly developing resistance to currently used drug therapy. The pyrazole ring is a key moiety reported to have a variety of biological activities. The current study aimed to design, synthesize and evaluate an array of pyrazole derivatives for potential antimalarial antileishmanial activity. The scheme for the synthesis of the pyrazole derivatives is presented. The antimalarial activity was assessed in-vivo on P. berghei ANKA infected mice to determine % parasitemia and mean survival time. The antileishmanial activity was assessed in-vitro, and IC50 for each compound was calculated. In-vivo acute toxicity and molecular docking on putative antimalarial and antileishmanial drug targets were performed using the most active compounds. All the derivatives exhibited significant antimalarial activity, the highest being 95% suppression of parasitemia with compounds 9a and 9b. The mean survival time of mice treated with these two compounds was also the highest (16-17 days) but was lower than chloroquine, the standard agent. Compounds 9a and 9b exhibited superior antileishmanial activity as compared to miltefosine. However, they were less potent than amphotericin. The compounds were safe and well-tolerated at toxic, oral and intraperitoneal, doses of 150mg/kg and 75mg/kg, respectively. Molecular docking of compound 9a revealed a good fitting pose with plasmodial Pf-DHFR enzyme and Lm-PTR1 enzyme, which explains the biological activity noted with this compound. Pyrazole derivatives 9a and 9b exhibited substantial dual antimalarial antileishmanial activity and may be a valuable scaffold for the design of further derivatives with antiprotozoal potential.

Crystal structure of 2-{[5-amino-1-(phenylsulfonyl)-1H-pyrazol-3-yl]oxy}-1-(4-methylphenyl)ethan-1-one

In the title compound, C18H17N3O4S, the pyrazole ring is planar, with the sulfur atom lying 0.558 (1) Å out of the ring plane. The NH2 group is involved in an intramolecular hydrogen bond to a sulfonyl oxygen atom; its other hydrogen atom forms an asymmetric three-centre hydrogen bond to the two oxygen atoms of the —O—CH2—C=O— grouping, via the 21 screw axis, forming a ribbon structure parallel to the b axis. Translationally adjacent, coplanar ribbons form a layer parallel to (10\overline{4}).

Formation of 1-(thiazol-2-yl)-4,5-dihydropyrazoles from simple precursors: synthesis, spectroscopic characterization and the structures of an intermediate and two products

Two new 1-(thiazol-2-yl)-4,5-dihydropyrazoles have been synthesized from simple precursors, and characterized both spectroscopically and structurally. In addition, two intermediates in the reaction pathway have been isolated and characterized, one of them structurally. The molecules of the intermediate (E)-1-(4-methoxyphenyl)-3-[4-(prop-2-ynyloxy)phenyl]prop-2-en-1-one, C19H16O3 (I), are linked by a combination of C—H...O and C—H...π(arene) hydrogen bonds to form ribbons. The products (RS)-5-(4-methoxyphenyl)-1-(4-phenythiazol-2-yl)-3-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydro-1H-pyrazole, C28H23N3O2S (II), and (RS)-5-(4-methoxyphenyl)-1-[4-(4-methylphenyl)thiazol-2-yl]-3-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydro-1H-pyrazole, C29H25N3O2S (III), are closely related – differing only by presence or absence of a methyl group at the arylthiazolyl substituent – and crystallize in an isomorphous setting. Both molecules contain an effectively planar dihydro-pyrazole ring, and possess an overall T-shaped structure, which is a characteristic of triaryl-substituted 4,5-dihydro-1-(thiazol-2-yl)pyrazole compounds. The crystal packing is characterized by intermolecular C—H...S and C—H...π (aryl/alkyne) interactions. A combination of two C—H...π(arene) hydrogen bonds links the product molecules into sheets.

Comparison of Conventional and Microwave Synthesis of Phenyl-1H-pyrazoles and Phenyl-1H-pyrazoles-4-carboxylic Acid Derivatives

Background: Molecules containing the pyrazole subunit considered that privileged scaffolds are of high importance due to their broad spectrum of pharmacological activities. For this reason, a method that is more efficient needs to be developed for the preparation of pyrazole derivatives. Objective: The purpose of this study was the optimisation of the conventional synthesis of the pyrazole ring and the oxidation of phenyl-1H-pyrazole-4-carbaldehyde to phenyl-1H-pyrazole-4-carboxylic acid through Microwave-Assisted Organic Synthesis (MAOS). Method: We performed a comparison between conventional synthesis and conventional synthesis with microwave heating using the synthesis of pyrazole ring described by Finar and Godfrey and, for the oxidation of phenyl-1H-pyrazole-4-carbaldehyde, the method described by Shriner and Kleiderer was used. Results: MAOS reduces the reaction time to obtain all compounds compared to conventional heating. At a temperature of 60°C, 5 minutes of reaction time, and power of 50W, the yield of phenyl-1H-pyrazoles (3a-m) compounds was in the range of 91 - 98% using MAOS, which is better than conventional heating (73 - 90%, 75ºC, 2 hours). An improvement in the yield for the oxidation reaction was also achieved with MAOS. The compounds (5a-m) were obtained with yields ranging from 62 - 92% (80ºC, 2 minutes, 150W), while the yields with conventional heating were in the range of 48 - 85% (80ºC, 1 hour). The 26 compounds were achieved through an easy work-up procedure with no chromatographic separation. The pure products were characterised by the spectral data obtained from IR, MS, 1H and 13C NMR or HSQC/HMBC techniques. Conclusion: The advantages of MAOS include short reaction time and increased yield, due to which it is an attractive option for the synthesis of pyrazole compounds.

Heterocyclic Compounds: Pharmacology of Pyrazole Analogs From Rational Structural Considerations

Low quality of life and life-threatening conditions often demand pharmacological screening of lead compounds. A spectrum of pharmacological activities has been attributed to pyrazole analogs. The substitution, replacement, or removal of functional groups on a pyrazole ring appears consistent with diverse molecular interactions, efficacy, and potency of these analogs. This mini-review explores cytotoxic, cytoprotective, antinociceptive, anti-inflammatory, and antidepressant activities of some pyrazole analogs to advance structure-related pharmacological profiles and rational design of new analogs. Numerous interactions of these derivatives at their targets could impact future research considerations and prospects while offering opportunities for optimizing therapeutic activity with fewer adverse effects.