Bio-inspired Reaction Research Articles

Collective Total Synthesis of β-Carboline-Type Monoterpenoid Indole Alkaloid Glycosides

AbstractThe collective and efficient asymmetric total syntheses of five β-carboline-type monoterpenoid indole alkaloid glycosides were achieved in fewer than thirteen steps. A Pictet–Spengler reaction with α-cyanotryptamine followed by the removal of the cyano group and autoxidation (aromatization) efficiently constructed the β-carboline motif. In addition, bioinspired reactions were developed to provide different alkaloid skeletons.

Advanced manufacturing concept of a bio-inspired reaction wheel rotor for small- and medium-sized constellation satellites

The increasing number of constellation satellites requires re-thinking of the design and manufacturing process for reaction wheel rotors. Mass optimisation of reaction wheel rotors leads to cost reduction and performance increase. Those optimisations can be realised by taking ideas from nature. Therefore, design principles of diatoms were screened, abstracted and implemented in an algorithm-based design process. In this way, a bio-inspired rotor was created, which considers launch and in-operation loads, is capable of up to 7500 RPM and shows a compact design with a diameter of 282,text {mm}. Regarding mechanical performance, an energy density of 4661,text {J kg}^{-1} and a mass moment of inertia ratio of 0.7584, which considers the component and an idealized design, could be achieved. Compared to a commercial rotor, this is equivalent to a similar inertia ratio and +85 % energy density, but +44 % mass due to manufacturing restrictions. Based on different boundary conditions, different first natural frequency for launch and operation conditions were obtained (658,text {Hz} and 210,text {Hz}). The new design was cast from nano-reinforced aluminium alloy (AlSi10Mg + Al2O3) in 3D-printed sand moulds that were produced via binder-jetting process. Thus, a hybrid manufacturing process was used, by combining additive manufacturing and casting. Post-processing of the cast part via turning and milling was performed to compensate distortion and achieve the required surface quality. Preliminary vibration measurements were performed, showing a large need for balancing to achieve low vibration emissions.

Bioinorganic Chemistry on Electrodes: Methods to Functional Modeling

One of the major goals of bioinorganic chemistry has been to mimic the function of elegant metalloenzymes. Such functional modeling has been difficult to attain in solution, in particular, for reactions that require multiple protons and multiple electrons (nH+/ne-). Using a combination of heterogeneous electrochemistry, electrode and molecule design one may control both electron transfer (ET) and proton transfer (PT) of these nH+/ne- reactions. Such control can allow functional modeling of hydrogenases (H+ + e- → 1/2 H2), cytochrome c oxidase (O2 + 4 e- + 4 H+ → 2 H2O), monooxygenases (RR'CH2 + O2 + 2 e- + 2 H+ → RR'CHOH + H2O) and dioxygenases (S + O2 → SO2; S = organic substrate) in aqueous medium and at room temperatures. In addition, these heterogeneous constructs allow probing unnatural bioinspired reactions and estimation of the inner- and outer-sphere reorganization energy of small molecules and proteins.

A Bio-Inspired Reaction Against Cyberattacks: AIS-Powered Optimal Countermeasures Selection

Nowadays, Information and Communication Technology (ICT) infrastructures play a crucial role for human beings, providing essential services at astonishing speed. Nevertheless, such a centrality of those infrastructures attracts the interest of ill-motivated actors that target such infrastructures with cyberattacks that are every day more sophisticated and more disruptive. In this alarming context, selecting the optimal set of countermeasures represents a primary need to react against the appearance of potentially dangerous threats effectively. With the motivation to contribute to develop ing faster and more effective response capabilities against them, the paper at hand introduces a novel cybersecurity reaction methodology based on Artificial Immune Systems (AIS), for which the evolutionary computing paradigm has been adopted. By leveraging the outstanding properties of these bio-inspired techniques, the selected countermeasures to defeat cyberthreats through cloning and mutation phases in an effort to improve the quality of the solution from a quantitative perspective, being able to adjust the risk to which the assets of the protected system are exposed. Exhaustive experiments demonstrate the feasibility of the proposed approach, reducing the risk in a more than acceptable time lapse.

Metal‐Nitrogen‐Doped Carbon Materials as Highly Efficient Catalysts: Progress and Rational Design

AbstractAs a typical class of single‐atom catalysts (SACs) possessing prominent advantages of high reactivity, high selectivity, high stability, and maximized atomic utilization, emerging metal‐nitrogen‐doped carbon (M‐N‐C) materials, wherein dispersive metal atoms are coordinated to nitrogen atoms doped in carbon nanomaterials, have presented a high promise to replace the conventional metal or metal oxides‐based catalysts. In this work, recent progress in M‐N‐C‐based materials achieved in both theoretical and experimental investigations is summarized and general principles for novel catalysts design from electronic structure modulating are provided. Firstly, the applications and mechanisms on the advantages and challenges of M‐N‐C‐based materials for a variety of sustainable fuel generation and bioinspired reactions, including the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR), and nanozyme reactions are reviewed. Then, strategies toward enhancing the catalytic performance by engineering the nature of metal ion centers, coordinative environment of active centers, carbon support, and their synergistic cooperation, are proposed. Finally, prospects for the rational design of next generation high‐performance M‐N‐C‐based catalysts are outlined. It is expected that this work will provide insights into high‐performance catalysts innovation for sustainable and environmental technologies.

Bioinspired Functional Catechol Derivatives through Simple Thiol Conjugate Addition.

The combination of the surface-adhesive properties of catechol rings and functional moieties conveying specific properties is very appealing to materials chemistry, but the preparation of catechol derivatives often requires elaborate synthetic routes to circumvent the intrinsic reactivity of the catechol ring. In this work, functional catechols are synthesized straightforwardly by using the bioinspired reaction of several functional thiols with o-benzoquinone. With one exception, the conjugated addition of the thiol takes place regioselectively at the 3-position of the quinone, and is rationalized by DFT calculations. Overall, this synthetic methodology provides a general and straightforward access to functional and chain-extended catechol derivatives, which are later tested with regard to their hydro-/oleophobicity, colloidal stability, fluorescence, and metal-coordinating capabilities in proof-of-concept applications.

水中バイオインスパイアード反応を鍵工程とするWIN 64821, ジトリプトフェナリン、ナセセアジンBの３段階合成

水中バイオインスパイアード反応を鍵工程とするWIN 64821, ジトリプトフェナリン、ナセセアジンBの３段階合成

Bio-inspired reaction diffusion system applied to image restoration

In this paper, we propose a new model of nonlinear and anisotropic reaction diffusion system applied to image restoration and to contrast enhancement. This model is based on a system of partial differential equations of type Fitzhugh-Nagumo. In the first, we give the comparison with the previous model, then, we show the robustness and the performance of our algorithm through a number of experimental results.

Bio-inspired reaction diffusion system applied to image restoration

Bio-inspired reaction diffusion system applied to image restoration

Synthesis, characterization, crystal structure, and reactivity of heterobimetallic dioxovanadium(V) complexes containing multidentate hydrazone ligands

Two new heterobimetallic complexes of the composition [(VO2)2(μ3-slsch){Na2(μ-H2O)2(H2O)2}]n (1) and [(VO2)2(μ3-npsch){Na2(μ-H2O)2(H2O)2}(DMF)]n (2) were obtained by reaction of the ligand and vanadium pentoxide in a 1:1 molar ratio in methanol in the presence of Na2CO3 (2 equivalents). The complexes obtained were characterized using various spectroscopic studies. The structures of both the complexes were established by single crystal X-ray crystallographic study. We have also explored the catalytic behavior of the complexes in oxidative bromination of phenol red, which is the bio-inspired reaction catalyzed by an enzyme haloperoxidase.

A Hybrid Catalyst for Light-Driven Green Molecular Transformations.

This Minireview is focused on the development of hybrid catalysts composed of photosensitizers and a metal complex, especially vitamin B12 derivatives. The semiconductor-metal complex composites are effective photocatalysts for molecular transformations due to the synergistic effect between the two components. The design of a B12 complex for the hybridization with TiO2 was simple and straightforward-cobyrinic acid, having seven carboxylic groups derived from naturally occurring B12 is stably immobilized on the TiO2 . By using the hybrid catalysts as mimics of B12 -dependent enzymes, light-driven reactions such as the dechlorination of organic halide pollutants, and radical-mediated isomerization proceeded catalytically. In addition to the enzyme-mimicking reactions, bioinspired reactions were also developed with the hybrid catalyst. The B12 -TiO2 hybrid catalyst was used for hydrogen evolution and alkene reduction by UV light irradiation, and the cobalt-hydrogen complex (Co-H complex) was considered to be a putative intermediate of the reactions. The multidisciplinary concept for the design of a hybrid catalyst is described in this Minireview.

Total synthesis of biologically active alkaloids using bio-inspired indole oxidation

Many tryptophan-based dimeric diketopiperazine (DKP) alkaloids including WIN 64821 and ditryptophenaline, which exhibit fascinating biological activities, have been isolated from fungi. These alkaloids possess a unique architecture; therefore several total syntheses of these compounds have been accomplished via bio-inspired reactions. Despite these elegant strategies, we were convinced that a more direct bio-inspired solution for the preparation of tryptophan-based DKP alkaloids was possible because in a true biosynthesis, direct dimerization of tryptophan occurs in aqueous media without incorporation of a protecting group on the substrates. Thus we developed direct bio-inspired dimerization reactions in aqueous, acidic media, along with a novel biomimetic pathway, to provide C2-symmetric and non-symmetric dimeric compounds from commercially available amine-free tryptophan derivatives using Mn(OAc)3, VOF3, and V2O5 as one-electron oxidants. In addition, concise two-pot or three-step syntheses of the naturally occurring dimeric DKP alkaloids (+)-WIN 64821, (-)-ditryptophenaline, and (+)-naseseazine B were accomplished with total yields of 20%, 13%, and 20%, respectively. The present synthesis has several noteworthy features: 1) the tryptophan-based C2-symmetric and non-symmetric dimeric key intermediates can be prepared on a multigram scale in one step; 2) the developed oxidation reaction was carried out in aqueous, acidic solution without deactivation of the metal oxidants; 3) protection of the primary amine can be avoided by salt formation in aqueous acid; 4) for the total two-pot operation, the reaction media are environmentally friendly water and ethanol; 5) satisfactory total yields are obtained compared with previously reported syntheses.

Bio-inspired Maillard-Like reactions enable a simple and sensitive assay for colorimetric detection of methylglyoxal.

A simple and selective assay for detecting methylglyoxal (MGO), a metabolite associated with diabetes, was developed by combining a bio-inspired chemical reaction with the anti-aggregation of gold nanoparticles. This assay could detect MGO at as low as 1 μM by the naked eye and 0.05 μM by UV/vis spectrometry, within the clinical range marking oxidative stress in diabetes, and demonstrated high selectivity over other physiologically relevant ketones and aldehydes.

Nucleation of iron oxide nanoparticles mediated by Mms6 protein in situ.

Biomineralization proteins are widely used as templating agents in biomimetic synthesis of a variety of organic-inorganic nanostructures. However, the role of the protein in controlling the nucleation and growth of biomimetic particles is not well understood, because the mechanism of the bioinspired reaction is often deduced from ex situ analysis of the resultant nanoscale mineral phase. Here we report the direct visualization of biomimetic iron oxide nanoparticle nucleation mediated by an acidic bacterial recombinant protein, Mms6, during an in situ reaction induced by the controlled addition of sodium hydroxide to solution-phase Mms6 protein micelles incubated with ferric chloride. Using in situ liquid cell scanning transmission electron microscopy we observe the liquid iron prenucleation phase and nascent amorphous nanoparticles forming preferentially on the surface of protein micelles. Our results provide insight into the early steps of protein-mediated biomimetic nucleation of iron oxide and point to the importance of an extended protein surface during nanoparticle formation.

Synthesis of Tryptophan-Based Dimeric Diketopiperazine Alkaloids Using Bioinspired Reactions

Tryptophan-based dimeric diketopiperazine alkaloids such as ditryptophenaline, WIN 64821, naseseazine A, and naseseazine B, exhibit a unique architecture and interesting biological activity. These alkaloids have been the subject of intense study by the synthetic organic chemistry community, and several elegant total syntheses have been discovered, especially using bioinspired strategies. Described herein is a brief overview of these alkaloid syntheses via bioinspired transformations as key steps.

Carbon Dioxide and Related Heterocumulenes at Zinc and Lithium Cations: Bioinspired Reactions and Principles

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Carbon dioxide and related heterocumulenes at zinc and lithium cations: bioinspired reactions and principles

This Perspective starts with the discussion of the properties of an interesting metalloenzyme (carbonic anhydrase, CA) that performs extremely successfully the activation of carbon dioxide. Conclusions from that are important for many synthetic procedures and include experimental and theoretical investigation (DFT calculations) of such metal mediated processes in the condensed and in the gas phase in which the zinc cation plays a dominant role. This is extended to the bio-analogue activation of further heterocumulenes such as COS, an important atmospheric trace gas, and CS(2). Novel metal complexes which serve as useful catalysts for the reactions (copolymerisations and cyclisation) of CO(2) and oxiranes are discussed subject to the inclusion of recently published DFT calculations. We continue with the discussion of the very general aspect of the insertion of CO(2) into metal-nitrogen bonds (formation of carbamates). This again is closely related to many biological or bio-analogue processes. We describe the synthesis and mechanistic aspects of characteristic metal carbamates of a wide variety of metals and include a discussion of the mechanistic aspects, especially for the formation of Mg(2+) and Li(+) carbamates and the formation of related cyclic products after addition of the heterocumulenes CO(2), Ph-NCO or CS(2) to novel ligands, the 4H-pyridin-1-ides which finally result in the formation of e.g. 1,3-thiazole-5(2H)-thiones.