The rising costs of pharmaceutical research are currently limiting the productivity of drug discovery and development, but can potentially be diminished via miniaturization of the synthesis and screening of new compounds. As droplet microarrays already present themselves as a versatile tool for highly miniaturized biological screening of various targets, their use for chemical synthesis is still limited. In this study, the influential palladium-catalyzed Suzuki–Miyaura reaction is successfully implemented at the nanoliter scale on droplet microarrays for the synthesis of an 800-compound library of biphenyls. Each reaction is carried out in individual 150 nL droplets. Remarkably, the synthesis of these 800 compounds requires a minimal amount of reagents, totaling 80 µmol, and a solvent volume of 400 µL. Furthermore, the cleavage kinetics and purity of the obtained biphenylic compounds are investigated. Via the solid-phase synthesis approach, the compounds could be purified from excess reactants and catalyst prior to the analysis and a UV-cleavable linker allows for fast and additive-free cleavage of each compound into the individual 100 nL droplet. This novel approach expands the toolbox of the droplet microarray for miniaturized high-throughput chemical synthesis and paves the way for future synthesis and screening of chemical compounds in a single platform. 相似文献
N-formylation is a common pre- and post-translational modification of the N-terminus or the lysine side chain of peptides and proteins that plays a role in the initiation of immune responses, gene expression, or epigenetics. Despite its high biological relevance, protocols for the chemical N-formylation of synthetic peptides are scarce. The few available methods are elaborate in their execution and the yields are highly sequence-dependent. We present a rapid, easy-to-use one-pot procedure that runs at room temperature and can be used to formylate protected peptides at both the N-terminus and the lysine side chain on the resin in near-quantitative yields. Only insensitive, storage-stable standard chemicals – formic acid, acetic anhydride, pyridine and DMF – are used. Formylation works for both short and long peptides of up to 34 amino acids and over the spectrum of canonical amino acids. 相似文献
Amphiphilic cyclic dipeptides are efficient supramolecular hydrogelators. They can be combined with molecular photoswitches to produce light-responsive soft materials, which can be applied in controlled drug delivery. Here it is reported that an arginine-containing cyclic dipeptide decorated with ortho-fluorinated azobenzene forms hydrogels under physiological conditions that can be reversibly liquefied upon exposure to visible light frequencies (green and violet, respectively). The addition of sodium alginate results in composite supramolecular hydrogels with increased gelating capacity supported with Coulombic interactions, which also reversibly dissipate upon irradiation. 相似文献
The purpose of this review is to present an overview of the patent landscape for catalysts used in hydrogenation reactions. Based on patent data extracted from PatBase®, we use predefined patent classifications as well as a keyword‐based search for our analyses. The results indicate that the number of patent families that protect heterogeneous catalysts grows twice as fast as that for their homogeneous counterparts. Furthermore, the data show a shift towards abundant and non‐toxic elements in heterogeneous catalysis, while the noble metals continue to dominate the patent landscape of homogeneous catalysis. A subsequent geographical analysis reveals that the high growth rates in heterogeneous catalysis, especially for nickel and iron, are driven by China. Conversely, patenting activities with regard to homogeneous catalysts mainly take place in the USA, the EU, and Japan. The subsequent keyword‐based search illustrates the continuous industrial relevance of enantioselective hydrogenation and transfer hydrogenation, as well as the rapidly increasing body of patents in hydrodeoxygenation. Setting these finding into context, we present and apply two concepts that are commonly used in patent analyses, namely the technology life cycle and the S‐curve. We conclude that hydrogenation catalysis has not reached its peak economic relevance yet and will continue to spark valuable patents and innovations in the future.
Recent years have witnessed considerable progress in the development of solar cells based on lead halide perovskite materials. However, their intrinsic instability remains a limitation. In this context, the interplay between the thermal degradation and the hydrophobicity of perovskite materials is investigated. To this end, the salt 1‐(4‐ethenylbenzyl)‐3‐(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctylimidazolium iodide (ETI), is employed as an additive in hybrid perovskites, endowing the photoactive materials with high thermal stability and hydrophobicity. The ETI additive inhibits methylammonium (MA) permeation in methylammonium lead triiodide (MAPbI3) occurring due to intrinsic thermal degradation, by inhibiting out‐diffusion of the MA+ cation, preserving the pristine material and preventing decomposition. With this simple approach, high efficiency solar cells based on the unstable MAPbI3 perovskite are markedly stabilized under maximum power point tracking, leading to greater than twice the preserved efficiency after 700 h of continuous light illumination and heating (60 °C). These results suggest a strategy to tackle the intrinsic thermal decomposition of MAI, an essential component in all state‐of‐the‐art perovskite compositions. 相似文献
Food fortification is an important nutrition intervention to fight micronutrient deficiencies and to reduce their incidence in many low‐ and middle‐income countries. Food fortification approaches experienced a significant rise in the recent years and have generated a lot of criticism. The present review aimed to shed light on the actual effect of food fortification approaches on the reduction of malnutrition. A set of 100 articles and reports, which have dealt with the impact of food fortification on malnutrition, were included in this review. This review identified a broad selection of local raw materials suitable for a food‐to‐food fortification approach. 相似文献
Ammonium dinitramide (ADN, NH4+ N(NO2)2−) based monopropellants are extremely promising as hydrazine replacement. Thermal igniters are attractive for ADN thrusters as they allow a more prompt ignition and may be better suited for larger engines (100‐500 N) compared to the currently used preheated catalysts. The results of an experimental campaign conducted on the ignition of two ADN‐based monopropellants (LMP‐103S and FLP‐106) with a torch igniter are presented. Several combustion chamber configurations have been tested to facilitate the ignition. Through the use of porous inlays in the chamber, ignition of both propellants was achieved. It was not possible, however, to achieve sustained combustion under the chosen test conditions. 相似文献
Microreactors offer several advantages compared to the industrial scale when developing new chemical processes. Especially the production and investment costs are low if polymer microreactors are generated by ultrasonic processes. In order to observe the chemical reaction and the flow configuration, these microreactors need to be optically transparent, mechanically stable, and chemically inert to several reagents. The manufacturing process of a transparent polymer plate reactor with a chemically inert surface coating by ultrasonic fabrication is described. Experimental characterization of the microreactors showed that they are leak tight up to a pressure difference of at least 300 kPa and the mixing times are in the range of milliseconds. 相似文献
Navigation assistance systems are aiming to improve safety and provide traffic optimization and have become more and more popular in a modern vehicular technology. The reason is given by the significant traffic increase and numerous congestion events in large cities, large complexity of road infrastructure, and unexpected or hazardous conditions that can be found on roads. This paper proposes an innovative navigation system solution that intelligently gathers traffic data provided by integrated car sensors and/or onboard security systems and uses it to warn other participants. System concepts, architecture, design, implementation, and performance evaluation aspects are presented, and tasks organization for an embedded cost‐effective implementation using a real‐time kernel is illustrated. 相似文献
