Robby Vroemans

A borrowing hydrogen approach to produce bio-based surfactants is described. Using amino acids and common alcohols without protecting groups, surfactants are synthesized in one step with a ruthenium catalyst, achieving nearly ideal atom economy, including Gemini surfactants and a quaternary ammonia salt, with remarkable surfactant properties and potential biodegradability, enhancing the broad application profile of these sustainable products.

Abstract

A borrowing hydrogen approach to produce bio-based surfactants is described. The process utilizes ubiquitous amino acids and common alcohols without protecting group manipulations. Surfactants are synthesized in a single step using a commercially available ruthenium-based catalyst in a waste-free manner with nearly ideal atom economy. The versatility of the products is shown by further derivatization resulting in novel Gemini surfactants and a related quaternary ammonia salt. The analysis of selected compounds shows remarkable properties as surfactants. Further studies show their potential biodegradability in nature, which enhances the broad application profile of the sustainable products prepared in this study.

Strike to react: This perspective discusses the fundamental concept of using piezoelectric materials for mechanocatalyzed organic synthesis. It outlines guidelines for designing piezocatalysts with enhanced performance, as well as the prospects and challenges of this emerging research direction.

Abstract

Piezoelectric materials offer great promise due to their ability to generate electric fields under mechanical stress, producing surface charges that drive otherwise kinetically sluggish redox reactions. The strained surfaces of these materials provide a unique advantage in controlling product selectivity and enabling reaction pathways that are unattainable with conventional methods. This perspective highlights advancements, challenges, and the future potential of piezoelectric materials in synthetic organic chemistry, with a focus on designing materials optimized for piezocatalyzed organic synthesis. Piezocatalysis is industrially relevant because of its operational simplicity, enabling mild, gram scale synthesis with reusable catalysts, minimal solvent use, and air tolerant conditions. It involves redox cycles that facilitate one electron redox events without requiring light exposure or electrical bias. Despite significant progress, many fundamental aspects are yet to be fully understood. One example is the correlation between piezoelectricity and catalytic activity, which is not always linear, as demonstrated by the comparison between tetragonal and cubic BaTiO₃. While cubic BaTiO₃ is not piezoelectric, it shows excellent catalytic activity in certain redox reactions such as arylation, dicarbonylation, and cyclization under mechanochemical conditions comparable to that of piezoelectric tetragonal BaTiO₃. Considering all these aspects, this perspective aims to stimulate discussion to advance this promising field in the right direction.

The analysis of metal leaching from jar walls remains an overlooked aspect during the development of a mechanochemical reaction. This comprehensive study reveals the processes of metal erosion and the formation of rusty particles under intense grinding conditions, alongside their significant impact on chemical reaction efficiency, selectivity, and outcome.

Abstract

Solvent-free techniques have gained considerable attention in recent years due to their environmental advantages and potential to enable chemical reactivities beyond the reach of traditional solution-based methods. Mechanochemistry has emerged as a groundbreaking approach to drive sustainable chemical processes. Despite its promise, some challenges still need to be explored, including the overlooked issue of material leaching during grinding, a phenomenon in which components from milling media or reaction vessels, such as stainless steel, unintentionally alter reaction outcomes. This study investigates the role of metal leaching in reducing arylnitrosamines by using a poorly soluble solid reagent, thiourea dioxide (TDO), focusing on stainless steel vessels. By comparing conventional mechanochemical methods with innovative solvent-free vibratory techniques, we assess the extent of metal contamination and its impact on reaction efficiency. These findings provide new insights into how material leaching influences chemical processes and offer valuable guidance for optimizing these forward-looking and green methodologies.

Nature, Published online: 13 January 2025; doi:10.1038/d41586-025-00058-7

Publication date: 28 February 2025

Source: Tetrahedron Letters, Volume 157

Author(s): Ani Deepthi, C.B. Meenakshy, Devika Krishnan

The story of the bow and arrow is the story of the use of intelligence to precisely reach a target. In the Front Cover image, this is replaced with a light source generating visible blue light, which is precisely used to synthesise the target heterocyclic compounds. The photochemical organic reactions achieved by using metal photocatalysts, non-metallic photocatalysts, or even without photocatalysts reported in the Review by S. Nagarajan and co-workers (DOI: 10.1002/ejoc.202401195) are a story of the use of intelligence in organic chemistry.

Two is better than one. The introduction of a second hydroxamic acid substituents along the cavity of a sulfonatocalix[4]arene improves the activity with which this compound detoxifies highly toxic nerve agents of the V-type to such an extent that its use as an antidote is now conceivable.

Abstract

Synthetic small molecule scavengers that rapidly detoxify nerve agents in vivo allow (pre)treatment of nerve agent poisoning. However, scavengers that detoxify persistent V-type nerve agents at pH 7.4 and 37 °C with sufficient efficiency are still unknown. The most promising compound to date is a monosubstituted sulfonatocalix[4]arene containing a hydroxamic acid group. This compound was used to investigate the effect of structural modifications on detoxification activity. While none of the monosubstituted calixarene derivatives considered in this context possessed higher activity than the parent compound, the disubstituted derivatives were very active, exhibiting half-lives of detoxification under the conditions of an established in vitro assay of <1.5 min. The rate of detoxification decreased with decreasing scavenger concentration, but even at a fourfold molar excess of the scavenger, complete detoxification of 2.5 μM solutions of some nerve agents could be achieved within one hour. These disubstituted calixarene derivatives thus bring synthetic scavengers for V-type nerve agents closer to application.