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Catalysis plays a crucial role in modern chemistry, with macrocyclic compounds like calixarenes serving as key players in organic transformations through supramolecular chemistry. These macrocycles, synthesized from phenol and formaldehyde condensation, exhibit a variety of conformations, such as cone and partial‐cone, due to their flexible structures. Their effectiveness as catalysts arises from their lipophilic cavities and the ease of functionalization on both the upper and lower rims. Water‐soluble calixarenes, in particular, have gained attention for their ability to interact with hydrophobic cavities, facilitating molecular recognition in aqueous environments. A landmark achievement in this field was Shinkai's synthesis of water‐soluble calix[4]arene in 1984, which involved sulphonation using tert‐butyl groups, resulting in compounds known for their low toxicity and encapsulation capabilities. This review provides a comprehensive overview of the advancements in sulphonated calixarenes as catalysts, emphasizing their diverse applications and potential for future development. Key catalytic reactions and their substrate scopes are discussed, along with future perspectives on how these compounds can further revolutionize catalytic processes. [ABSTRACT FROM AUTHOR]

Polylactide (PLA), a biocompatible and biodegradable polymer, is widely used in diverse biomedical applications. However, the industry standard for converting lactide into PLA involves toxic tin (Sn)‐based catalysts. To mitigate the use of these harmful catalysts, other environmentally benign metal‐containing agents for efficient lactide polymerization have been studied, but these alternatives are hindered by complex synthesis processes, reactivity issues, and selectivity limitations. To overcome these shortcomings, we explored the catalytic activity of Cu‐(Phe)2 and Zn‐(Phe)2 metal‐amino acid co‐assemblies as potential catalysts of the ring‐opening polymerization (ROP) of lactide into PLA. Catalytic activity of the assemblies was monitored at different temperatures and solvents using 1H‐NMR spectroscopy to determine the catalytic parameters. Notably, Zn‐(Phe)2 achieved >99% conversion of lactide to PLA within 12 h in toluene under reflux conditions and was found to have first‐order kinetics, whereas Cu‐(Phe)2 exhibited significantly lower catalytic activity. Following Zn‐(Phe)2‐mediated catalysis, the resulting PLA had an average molecular weight of 128 kDa and a dispersity index of 1.25 as determined by gel permeation chromatography. Taken together, our minimalistic approach expands the realm of metal‐amino acid‐based supramolecular catalytic nanomaterials useful in the ROP of lactide. This advancement shows promise for the future design of simplified biocatalysts in both industrial and biomedical applications. [ABSTRACT FROM AUTHOR]

ImportanceHigher dietary intake of the essential fatty acid docosahexaenoic (DHA) has been associated with better cognitive performance in several epidemiological studies. Animal and in vitro studies also indicate that DHA prevents amyloid deposition in the brain.ObjectiveTo determine the association between serum DHA levels, cerebral amyloidosis, and the volumes of brain areas affected by Alzheimer disease.Design, settings, and participantsCross-sectional analysis of serum DHA levels together with measures of amyloid deposition (Pittsburgh Compound B index), brain volumes, and neuropsychological testing scores from 61 participants in the Aging Brain Study. The study was conducted between June 2008 and May 2013, and the data were analyzed between October 2015 and April 2016. Linear models were adjusted for age, sex, years of education, and apolipoprotein E status.Main outcomes and measuresSerum DHA levels with cerebral amyloidosis measured using PIB PET.ResultsSamples were available from 61 Aging Brain Study participants (41 women and 20 men) who underwent amyloid PET imaging. The mean (SD) age of the participants was 77 (6) years and ranged from 67 to 88 years. Serum DHA levels (percentage of total fatty acids) were 23% lower in participants with cerebral amyloidosis than those without (0.97 vs 1.25, P = .007) and were inversely correlated with brain amyloid load (r = -0.32, P = .01) independent of age, sex, apolipoprotein E genotype, and years of education. Moreover, greater serum DHA levels were positively associated with brain volume in several subregions affected by AD, in particular the left subiculum (r = 0.38, P = .005) and the left entorhinal volumes (r = 0.51, P = .001). Serum DHA levels were also associated with nonverbal memory scores (r = 0.28, P = .03).Conclusions and relevanceIn this study, serum DHA levels were associated with pathogenesis of cerebral amyloidosis and with preservation of entorhinal and hippocampal volumes. These findings suggest an important role for DHA metabolism in brain amyloid deposition during the preclinical or early symptomatic stages of Alzheimer disease.

The demand for novel, fast‐acting, and effective antimalarial medications is increasing exponentially. Multidrug resistant forms of malarial parasites, which are rapidly spreading, pose a serious threat to global health. Drug resistance has been addressed using a variety of strategies, such as targeted therapies, the hybrid drug idea, the development of advanced analogues of pre‐existing drugs, and the hybrid model of resistant strains control mechanisms. Additionally, the demand for discovering new potent drugs grows due to the prolonged life cycle of conventional therapy brought on by the emergence of resistant strains and ongoing changes in existing therapies. The 1,2,4‐trioxane ring system in artemisinin (ART) is the most significant endoperoxide structural scaffold and is thought to be the key pharmacophoric moiety required for the pharmacodynamic potential of endoperoxide‐based antimalarials. Several derivatives of artemisinin have also been found as potential treatments for multidrug‐resistant strain in this area. Many 1,2,4‐trioxanes, 1,2,4‐trioxolanes, and 1,2,4,5‐tetraoxanes derivatives have been synthesised as a result, and many of these have shown promise antimalarial activity both in vivo and in vitro against Plasmodium parasites. As a consequence, efforts to develop a functionally straight‐forward, less expensive, and vastly more effective synthetic pathway to trioxanes continue. This study aims to give a thorough examination of the biological properties and mode of action of endoperoxide compounds derived from 1,2,4‐trioxane‐based functional scaffolds. The present system of 1,2,4‐trioxane, 1,2,4‐trioxolane, and 1,2,4,5‐tetraoxane compounds and dimers with potentially antimalarial activity will be highlighted in this systematic review (January 1963–December 2022). [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) are promising carbonaceous nanomaterials fortuitously discovered in 2004. CQDs are the rising stars in the nanotechnology ensemble because of their unique properties and widespread applications in sensing, imaging, medicine, catalysis, and optoelectronics. CQDs are notable for their excellent solubility and effective luminescence and, as a result, they are also known as carbon nanolights. Many strategies are used for the efficient and economical preparation of CQDs; however, CQDs prepared from waste or green sustainable methods have greater requirements due to their safety and ease of synthesis. Sustainable chemical strategies for CQDs have been developed, emphasizing green synthetic methodologies based on 'top‐down' and 'bottom‐up' approaches. This review summarizes many such studies relevant to the development of sustainable methods for photoluminescent CQDs. Furthermore, we have emphasized recent advances in CQDs' photoluminescence applications in chemical and biological fields. Finally, a brief overview of synthetic processes using the green source and their associated applications are tabulated, providing a clear understanding of the new optoelectronic materials. [ABSTRACT FROM AUTHOR]

Novel oxygen-depleted calix[4]arenes containing fused carbazole moieties demonstrate AIEgen behavior in aqueous solutions. This phenomenon leads to highly sensitive detection of nitric-oxide guest molecules because it affects intra- and intermolecular energy transfer within aggregates. [ABSTRACT FROM AUTHOR]