Pyrazole, a five membered heteroaromatic ring with two nitrogen atoms is of immense significance. Presence of this nucleus in the pharmacological agents of diverse therapeutic categories viz. ...antianxiety, anti-inflammatory, antipsychotic, anticancer, antiobesity, analgesic, antipyretic etc. has made it an indispensable anchor for design and development of new pharmacological agents. Owing to the development of novel and new pyrazole based therapeutic agents at a faster pace, there is a need to couple the latest information with previously available information to understand status of this moiety in medicinal chemistry research. The review herein highlights the therapeutic worth of pyrazole derivatives. Several therapeutically active pyrazole based derivatives developed by numerous scientists across the globe are reported here.
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•Pyrazole: Five membered heterocyclic ring with diverse pharmacological activities.•Provides an overview of various established and reported drugs containing pyrazole moiety.•Helpful for researchers planning to work on.
An iridium catalyzed method for the synthesis of functionalized cyclohexanes from methyl ketones and 1,5-diols is described. This process operates by two sequential hydrogen borrowing reactions, ...providing direct access to multisubstituted cyclic products with high levels of stereocontrol. This methodology represents a novel (5 + 1) strategy for the stereoselective construction of the cyclohexane core.
The application of an iridium-catalyzed hydrogen borrowing process to enable the formation of α-branched ketones with higher alcohols is described. In order to facilitate this reaction, ...ortho-disubstituted phenyl and cyclopropyl ketones were recognized as crucial structural motifs for C–C bond formation. Having optimized the key catalysis step, the ortho-disubstituted phenyl products could be further manipulated by a retro-Friedel–Crafts acylation reaction to produce synthetically useful carboxylic acid derivatives. In contrast, the cyclopropyl ketones underwent homoconjugate addition with several nucleophiles to provide further functionalized branched ketone products.
Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control ...over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5‐diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies.
A catalytic asymmetric method is described for the synthesis of enantioenriched cyclohexanes from racemic 1,5‐diols by hydrogen borrowing catalysis. This reaction is mediated by a chiral iridium(I) complex which is able to impart high levels of enantioselectivity to the process.
A hydrogen borrowing reaction employing secondary alcohols and Ph* (Me5C6) ketones to give β-branched carbonyl products is described (21 examples). This new C–C bond forming process requires low ...loadings of Cp*IrCl22, relatively low temperatures, and up to 2.0 equiv of the secondary alcohol. Substrate-induced diastereoselectivity was observed, and this represents the first example of a diastereoselective enolate hydrogen borrowing alkylation. By utilizing the Ph* group, the β-branched products could be straightforwardly cleaved to the corresponding esters or amides using a retro-Friedel–Crafts reaction. Finally, this protocol was applied to the synthesis of fragrance compound (±)-3-methyl-5-phenylpentanol.
To investigate outcomes for small versus large pupils in cataract surgery using different pupil expansion techniques.
Retrospective case-series reviewing 20,175 patients' cataract surgery electronic ...medical records at Moorfields Eye Clinic in Bedford Hospital NHS Trust from January 2010 to April 2020. Outcomes such as visual acuity (VA), intraocular pressure, intraoperative, post-operative complications were recorded and small pupil expansion device outcome.
One thousand, four hundred twenty-six patients were identified as having small pupil (SP). Of these, 1110 patients (77.8%) had interventions to expand the pupil including 447 (31.3%) with intracameral phenylephrine (IC PE) alone, 194 (13.6%) with iris hooks and 469 (32.9%) with a Malyugin ring. The large pupil (LP) group had a statistically significant greater gain in VA than the SP group (p < 0.05). SPs had a significantly higher rate of intraocular complications including posterior capsular rupture (PCR) with vitreous loss (OR 2.75, p < 0.001). There was also a significantly higher rate of post-operative complications such as corneal oedema (OR 2.64, p < 0.001) and anterior uveitis (OR 2.11, p < 0.001) in the SP group. However, VA improvement and complications between the different pupil expansion groups showed no significant differences (p > 0.05) except for a greater rate of iris tears in the Malyugin group (p < 0.05).
To date, this is the largest reported case-series comparing Malyugin rings and iris hooks with other pupil expansion techniques. The various techniques to expand pupil size appear to be safe and equally effective in improving VA with a similar rate of complications except for a greater rate of iris tears with Malyugin ring.
A “turn on” time-resolved fluorometric aptasensor is described for the simultaneous detection of zearalenone (ZEN), trichothecenes A (T-2), and aflatoxin B
1
(AFB
1
). Multicolor-emissive ...nanoparticles doped with lanthanide ions (Dy
3+
, Tb
3+
, Eu
3+
) were functionalized with respective aptamers and applied as a bioprobe, and tungsten disulfide (WS
2
) nanosheets are used as a quencher of time-resolved fluorescence. The assay exploits the quenching efficiency of WS
2
and the interactions between WS
2
and the respective DNA aptamers. The simultaneous recognition of the three mycotoxins can be performed in a single solution. In the absence of targets, WS
2
is easily adsorbed by the mixed bioprobes via van der Waals forces between nucleobases and the WS
2
basal plane. This brings the bioprobe and WS
2
into close proximity and results in quenched fluorescence. In the presence of targets, the fluorescence of the bioprobes is restored because the analytes react with DNA probe and modify their molecular conformation to weaken the interaction between the DNAs and WS
2
. Under the optimum conditions and at an excitation wavelength of 273 nm, the time-resolved fluorescence intensities (peaking at 488, 544 and 618 nm and corresponding to emissions of Dy
3+
, Tb
3+
and Eu
3+
) were used to quantify ZEN, T-2 and AFB
1
, respectively, with detection limits of 0.51, 0.33 and 0.40 pg mL
−1
and a linear range from 0.001 to 100 ng mL
−1
. The three mycotoxins can be detected simultaneously without mutual interference. The assay was applied to the quantification of ZEN, T-2 and AFB
1
in (spiked) maize samples. This homogeneous aptamer based assay can be performed within 1 h. Conceivably, it can become an alternative to other heterogeneous methods such as the respective enzyme-linked immunosorbent assays.
Graphical abstract
Schematic presentation of an aptasensor for simultaneous detection of zearalenone, trichothecenes A and aflatoxin B
1
using aptamer modified time-resolved fluorescence nanoparticles as signalling probes and tungsten disulfide as the quencher. This assay shows lower detection limit and requires no washing steps.
Alumina-graphene hybrid fillers (Gr-Al2O3) were synthesized and added to the epoxy matrix to improve thermal properties of the epoxy composite. The alumina particles were surface modified with silane ...coupling agents like 3-Aminopropyl triethoxysilane (A-Al2O3). 3-Glycidyloxypropyl trimethoxysilane (GPTMS) was used for the surface modification of the graphene (G-Graphene). These modifications on the filler surface help to develop the interface between the fillers and the epoxy matrix, which might help to form the effective 3D thermal conductive networks. The generation of these 3D networks facilitated in reducing the Kapitza resistance and increases the transportation of phonons in the matrix, Furthermore; it improved the integral procedure decomposition temperature (IPDT) and activation energy (Ea) of the composite. Alumina-graphene hybrid filled epoxy composite (hAG-Epoxy) with 50 vol% of hybrid filler (Gr-Al2O3) expressed the considerable improvement in in-plane thermal conductivity and IPDT by ∼8.4 and ∼3.1 folds in comparison with neat epoxy, respectively. The significant improvement in thermal conductivity was related to the generation of effective 3D thermal conductive pathways formed by 2D graphene and 1D alumina in the composite.
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•Hybridization of alumina and graphene is carried through functionalization with silane coupling agents.•Surface modifications helps appropriate bonding between fillers and further helps in developing good interface with epoxy matrix, decrease thermal interface resistance and increase phonon transportation.•The thermal conductivity is enhanced upto to 1.67 W m−1. K−1, which is ∼8 fold with compare to neat epoxy.•The experiments is also compare with Maxwell and Bruggeman's model for effective thermal conductivity.•The hybrid filler improves the thermal conductivity and thermal stability of the epoxy composite.
Green biomass is a renewable and biodegradable material that has the potential use to trap urea to develop a high-efficiency urea fertilizer for crops' better performance. Current work examined the ...morphology, chemical composition, biodegradability, urea release, soil health, and plant growth effects of the SRF films subjected to changes in the thickness of 0.27, 0.54, and 1.03 mm. The morphology was examined by Scanning Electron Microscopy, chemical composition was analyzed by Infrared Spectroscopy, and biodegradability was assessed through evolved CO2 and CH4 quantified through Gas Chromatography. The chloroform fumigation technique was used for microbial growth assessment in the soil. The soil pH and redox potential were also measured using a specific probe. CHNS analyzer was used to calculate the total carbon and total nitrogen of the soil. A plant growth experiment was conducted on the Wheat plant (Triticum sativum). The thinner the films, the more they supported the growth and penetration of the soil's microorganisms mainly the species of fungus possibly due to the presence of lignin in films. The fingerprint regions of the infrared spectrum of SRF films showed all films in soil changed in their chemical composition due to biodegradation but the increase in the thickness possibly provides resistance to the films' losses. The higher thickness of the film delayed the rate and time for biodegradation and the release of methane gas in the soil. The 1.03 mm film (47% in 56 days) and 0.54 mm film (35% in 91 days) showed the slowest biodegradability as compared to the 0.27 mm film with the highest losses (60% in 35 days). The slow urea release is more affected by the increase in thickness. The Korsymer Pappas model with release exponent value of < 0.5 explained the release from the SRF films followed the quasi-fickian diffusion and also reduced the diffusion coefficient for urea. An increase in the pH and decrease in the redox potential of the soil is correlated with higher total organic content and total nitrogen in the soil in response to amending SRF films with variable thickness. Growth of the wheat plant showed the highest average plant length, leaf area index and grain per plant in response to the increase in the film's thickness. This work developed an important knowledge to enhance the efficiency of film encapsulated urea that can better slow the urea release if the thickness is optimized.
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