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Nature, Published online: 25 April 2024; doi:10.1038/d41586-024-01246-7

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We report an idea for the synthesis of oligopeptides using a solvent-free ball milling approach. Our concept is inspired by block play, in which it is possible to construct different objects using segments (blocks) of different sizes and lengths. We prove that by having a library of short peptides and employing the ball mill mechanosynthesis (BMMS) method, peptides can be easily coupled to form different oligopeptides with the desired functional and biological properties. Optimizing the BMMS process we found that the best yields we obtained when TBTU and cesium carbonate were used as reagents. The role of Cs2CO3 in the coupling mechanism was followed on each stage of synthesis by 1H, 13C and 133Cs NMR employing Magic Angle Spinning (MAS) techniques. It was found that cesium carbonate acts not only as a base but is also responsible for the activation of substrates and intermediates. The unique information about the BMMS mechanism is based on the analysis of 2D NMR data. The power of BMMS is proved by the example of different peptide combinations, 2+2, 3+2, 4+2, 5+2 and 4+4. The tetra-, penta-, hexa-, hepta- and octapeptides obtained under this project were fully characterized by MS and NMR techniques.

Alkyl levulinates (ALs) are strategic compounds for the development of sustainable energy transition. In this regard, the direct alcoholysis of fructose and inulin for the selective ethyl levulinate (EL) production was investigated with a One-Factor-At-a-Time (OFAT) approach employing diluted H2SO4 as catalyst to clarify the role of the main reaction parameters (substrate and acid loadings, temperature, reaction time). The OFAT investigation on fructose ethanolysis allowed to reach the EL yield of 91.5 mol%. The inulin ethanolysis was then optimized adopting the multivariate approach based on the Response Surface Methodology (RSM), which highlighted the interplay of the reaction parameters on the selective EL production. This allowed to identify the optimal conditions to reach the highest EL yield (up to 89.3 mol%) and also those which ensured the highest EL concentration, adopting a substrate loading (14 wt%) higher than the majority ones reported in the literature according to the high gravity approach, and the lowest diethyl ether (DEE) by-product yield. The DEE formation is scarcely investigated in the literature, but it can negatively influence the alcoholysis process, thus it was considered in this work. Moreover, the humin solid residue was deeply characterized to envisage its possible applications, under a circular economy perspective.

Nature, Published online: 16 April 2024; doi:10.1038/d41586-024-01012-9

An ambitious investigation has analysed discourse on eight social-media platforms, covering a vast array of topics and spanning several decades. It reveals that online conversations increase in toxicity as they get longer — and that this behaviour persists despite shifts in platforms’ business models, technological advances and societal norms.

Chemistry has the potential to drive global sustainability efforts, but how to ensure its optimal impact is not always obvious. Through analysis of green, circular, and sustainable chemistry concepts, this Scientific Perspective identifies unified triple E priorities, covering environmental, economic, and equity pillars, and categorizes associated metrics. Case studies illustrate how these can be used to guide research and decisions.

Abstract

Chemistry, a vital tool for sustainable development, faces a challenge due to the lack of clear guidance on actionable steps, hindering the optimal adoption of sustainability practices across its diverse facets from discovery to implementation. This Scientific Perspective explores established frameworks and principles, proposing a conciliated set of triple E priorities anchored on Environmental, Economic, and Equity pillars for research and decision making. We outline associated metrics, crucial for quantifying impacts, classifying them according to their focus areas and scales tackled. Emphasizing catalysis as a key driver of sustainable synthesis of chemicals and materials, we exemplify how triple E priorities can practically guide the development and implementation of processes from renewables conversions to complex customized products. We summarize by proposing a roadmap for the community aimed at raising awareness, fostering academia–industry collaboration, and stimulating further advances in sustainable chemical technologies across their broad scope.

In the last decades, numerous efforts have been made to replace metal catalysts with cheaper and earth-abundant alternatives or the complete exclusion of metals in cross-coupling reactions, maintaining high efficiency of the target transformation. However, follow-up studies often revealed the role of metal impurities in the catalytic process. Thus, active metal impurities lead to mechanistic misinterpretations, could initiate erroneous research directives, and can lead to severe reproducibility problems. Milestone precedents of impurity effect in cross-coupling reactions are well documented in the literature. Interestingly, this fallacy has occurred repeatedly over the years due to the lack of thorough mechanistic studies and the appropriate research study scheme for identifying the impurity effect. Herein, we propose a guideline elucidating the real catalyst of future catalytic transformations that could eliminate mechanistic misinterpretation and help exclude the role of impurities in novel catalytic processes. Although this guideline mainly focuses on problems related to trace transition metals, it also offers the base for more general catalyst research.

New furan, carvone and limonene-based carbamates have been synthesized with high regioselectivity under solvent-free and mild reaction conditions. Moreover, a detailed study on the reaction conditions allowed for the drastic reduction of the TBD loading with almost no effect on the regioselectivity.

Abstract

The regioselective synthesis of carbamates from bio-derived cyclic carbonates and amines by using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as an organocatalyst is reported. This methodology led to the preparation of a wide range of bio-sourced hydroxyurethanes from furan-, carvone- and limonene-based scaffolds under solvent-free and mild reaction conditions. Moreover, a comprehensive analysis of the process allowed us to optimize the catalyst loading with little or no impact on the process regioselectivity.

Nature, Published online: 27 March 2024; doi:10.1038/d41586-024-00951-7

Whether for April Fools’ Day or year-round, practical jokes allow scientists to tap into creative thinking while building group camaraderie.

Synlett
DOI: 10.1055/a-2283-5829

Azo compounds with a high density, high enthalpy, and excellent detonation performance have received increasing research attention. The conventional method of chemical dehydrogenation that is used to form azo compounds involves the use of strong oxidants, resulting in environmental pollution. Electrochemical organic synthesis is considered an old method and a new technology. In this work, azofurazan tetrazole {H2AzFT; 5,5′-[diazene-1,2-diylbis(1,2,5-oxadiazole-4,3-diyl)]bis-1H-tetrazole} and azofurazan hydroxytetrazole (H2AzFTO) were synthesized by a green and efficient electrochemical dehydrogenation coupling of 5-(4-aminofurazan-3-yl)-1H-tetrazole and 5-(4-aminofurazan-3-yl)-1-hydroxytetrazole, respectively. The structures of H2AzFT and (NH4)2AzFTO were fully characterized by infrared spectroscopy, nuclear magnetic resonance, and elemental analysis, and their thermal stabilities were determined by differential thermal analysis.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
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Nature, Published online: 27 March 2024; doi:10.1038/d41586-024-00922-y

Analysis of a random selection of papers shared on social media showed no causative link between posting and citations.

Synlett
DOI: 10.1055/s-0042-1751569

Over the past two decades, bioorthogonal chemistry has profoundly impacted various chemistry-related fields, including chemical biology and drug delivery. This transformative progress stems from collaborative efforts involving chemists and biologists, underscoring the importance of interdisciplinary research. In this Account, we present the developments in bioorthogonal chemistry within our Institute for Molecules and Materials at Radboud University. The chemistry disclosed here spans from strained alkynes and alkenes to drug release and bioconjugation strategies, mirroring the extensive scope provided by bioorthogonal chemistry. By reflecting on the chemistry originating at Radboud University, this Account emphasizes that teamwork is essential for driving significant progress in bioorthogonal chemistry.1 Introduction2 Providing BCN as a Robust Bioorthogonal Tool for Chemical Biology and Beyond3 Towards Readily Available Click-to-Release trans-Cyclooctenes4 Giving Molecules Guidance5 Next Generation of Bioconjugation Strategies: Dynamic Click Chemistry6 Conclusions
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
Table of contents  |  Abstract  |  open access Full text

Nature, Published online: 13 March 2024; doi:10.1038/d41586-024-00727-z

A hiring manager reveals the lessons he learnt when transitioning from a PhD programme to industry.

Paracetamol can be produced from p-hydroxybenzamide at >95 % purity in 90 % yield. Aqueous ammonia treatment of poplar or oil palm empty fruit bunches forms p-hydroxybenzamide. Under continuous processing conditions, a Hofmann rearrangement converts p-hydroxybenz-amide to p-aminophenol, then liquid/liquid extraction combined with acid/base chemistry and acetylation purifies, forms, and isolates paracetamol.

Abstract

As we work to transition the modern society that is based on non-renewable chemical feedstocks to a post-modern society built around renewable sources of energy, fuels, and chemicals, there is a need to identify the renewable resources and processes for converting them to platform chemicals. Herein, we explore a strategy for utilizing the p-hydroxybenzoate in biomass feedstocks (e. g., poplar and palm trees) and converting it into a portfolio of commodity chemicals. The targeted bio-derived product in the first processing stage is p-hydroxybenzamide produced from p-hydroxybenzoate esters found in the plant. In the second stage a continuous reaction process converts the p-hydroxybenzamide to p-aminophenol via the Hofmann rearrangement and recovers the unreacted p-hydroxybenzamide. In the third stage the p-aminophenol can be acetylated to form paracetamol, which is readily isolated by liquid/liquid extraction at >95 % purity and an overall p-hydroxybenzamide-to-paracetamol process yield of ~90 %. We explore how utilization of protecting groups alters the challenges in this process and expands the portfolio of possible products to include p-(methoxymethoxy)aniline and N-acetyl-p-(methoxymethoxy)aniline. These target compounds could become value-added renewably-sourced platform chemicals that could be used to produce biodegradable plastics, pigments, and pharmaceuticals.