Abstract
The article considers a new electrical circuit of a microelectronicradio-frequency measuring temperature transducer with a thermosensitive resistive element based on a complex compound of ...heterometallicβ-diketonate.The main characteristics of the researched radio-frequency temperature transducer with a thermosensitive resistive element based on a complex compound of heterometallic β-diketonate are obtained: the dependences of the active and reactive components of the full impedance of the radio-frequency measuring temperature transducer, the conversion function and the sensitivity equation.
An efficient method for the metal‐free deaminative borylation of alkylamines, using bis(catecholato)diboron as the boron source, to directly synthesize various alkyl potassium trifluoroborate salts ...is introduced. The key to this high reactivity is the utilization of pyridinium salt activated alkylamines, with a catalytic amount of a bipyridine‐type Lewis base as a promoter. This transformation shows good functional‐group compatibility (e.g., it is unimpeded by the presence of a ketone, indole, internal alkene, or unactivated alkyl chloride) and can serve as a powerful synthetic tool for borylation of amine groups in complex compounds. Mechanistic experiments and computations suggest a mechanism in which the Lewis base activated B2cat2 unit intercepts an alkyl radical generated by single‐electron transfer (SET) from a boron‐based reductant.
N to B: A mild catalytic system was developed for the preparation of alkyl potassium trifluoroborate salts by C−N bond cleavage. This method has good functional‐group compatibility and can serve as a powerful synthetic tool for late‐stage borylative cleavage of C−N bonds in complex compounds. dtbpy=4,4′‐di‐tert‐butyl‐2,2′‐bipyridine.
Radical‐initiated difunctionalization of alkenes is one of the most important methods in organic synthesis and medicinal chemistry, which can be applied to synthesize value complex compounds as well ...as structural motifs that found in bioactive natural products and pharmaceuticals. In recent years, impressive progress have been made in this area with ideal silver catalysis. Here, we summarize recent advances in silver‐mediated radical difunctionalization of alkenes for the formation of diverse bonds, including 1) two‐component radical difunctionalization reactions enabled by an intramolecular cyclization process toward various cyclic compounds and 2) three‐component radical difunctionalization reactions leading to complex linear compounds. These silver‐mediated radical alkene difunctionalization transformations are general initiated by different radicals, such as carbon‐, oxygen‐, sulfur‐, phosphinyl‐, and halogen‐center radicals, followed by terminated with nucleophiles to form two new bonds in a single reaction.
Ag catalysis: Recent advances in the silver‐mediated intermolecular radical 1,2‐difunctionalization of alkenes are summarized. These reaction are classified by the substrate type and radical regents. Two new C−C/C−C bonds, C−C/C−X bonds (X=F, O, S…) and C−X/C−X bonds (X=O, Br, I…) could be constructed in a single reaction.
A copper catalytic system was established for the stereoselective hydrodefluorination of gem‐difluoroalkenes through C−F activation to synthesize various Z fluoroalkenes. H2O is used as the hydrogen ...source for the fluorine acceptor moiety. This mild catalytic system shows good‐functional group compatibility, accepting a range of carbonyls as precursors to the gem‐difluoroalkenes, including aliphatic, aromatic, and α,β‐unsaturated aldehydes and even ketones. It serves as a powerful synthetic method for the late‐stage modification of complex compounds.
From A(ll) to Z: A copper catalytic system was established for the stereoselective hydrodefluorination of carbonyl‐derived gem‐difluoroalkenes with water through C−F activation. This route employs readily available aldehydes or ketones, cheap fluorine and hydrogen sources, and an earth‐abundant metal as the catalyst, and it can be employed to construct Z fluoroalkenes without considering the Z/E configuration of the substrates or intermediates.
Medicago sativa L. (alfalfa) is a herbaceous plant of great importance in agriculture. The chemical composition of the substrate affects the mineral supply as well as the growth, development and ...metabolism of the plants. Therefore, the aim of this experiment is to determine the influence of zinc, copper and platinum complexes (ZnCl2(en), CuCl2(en), cis-PtCl2(NH3)2, en = ethylenediamine) on the germination and growth of alfalfa and on the content of phenolic compounds. Alfalfa seeds were sown in three separate groups and treated with the above complexes, the fourth group being the control. The growth of the vegetative part was observed after the tenth, twentieth and thirtieth day. The percentage of germination was recorded for each experimental group. At the end of the treatment, the aerial parts of each group were dried and prepared for extraction with methanol, after which the quantitative composition of phenolic compounds was analyzed by liquid chromatography.The results obtained show that CuCl2(en) has the best effect on the germination percentage, while the treatment with the platinum(II) complex - cis-PtCl2(NH3)2 showed a significant effect on the growth of alfalfa. The results of chromatographic analysis showed that ZnCl2(en) and CuCl2(en) improved the synthesis of phenolic compounds of alfalfa, with a significant content of catechins in the treatment with the copper complex compared to the control group. Based on the obtained results, it was concluded that the complex compounds have a significant effect on the germination, growth and phenolic compounds content of alfalfa, with different effects for each of the studied processes.
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•Medicago sativa L. (alfalfa) is plant with high nutritional value.•The influence of metal complexes on the germination and growth of alfalfa was investigated.•The effects of these complexes on the content of phenolic compounds was also evaluated.•The complexes had a positive effect on seed germination and cis-PtCl2(NH3)2 had a significant effect on increasing the concentration of almost all phenolic compounds.
Late-stage functionalization (LSF) introduces functional group or structural modification at the final stage of the synthesis of natural products, drugs, and complex compounds. It is anticipated that ...late-stage functionalization would improve drug discovery's effectiveness and efficiency and hasten the creation of various chemical libraries. Consequently, late-stage functionalization of natural products is a productive technique to produce natural product derivatives, which significantly impacts chemical biology and drug development. Carbon–carbon bonds make up the fundamental framework of organic molecules. Compared with the carbon–carbon bond construction, the carbon–carbon bond activation can directly enable molecular editing (deletion, insertion, or modification of atoms or groups of atoms) and provide a more efficient and accurate synthetic strategy. However, the efficient and selective activation of unstrained carbon–carbon bonds is still one of the most challenging projects in organic synthesis. This review encompasses the strategies employed in recent years for carbon–carbon bond cleavage by explicitly focusing on their applicability in late-stage functionalization. This review expands the current discourse on carbon–carbon bond cleavage in late-stage functionalization reactions by providing a comprehensive overview of the selective cleavage of various types of carbon–carbon bonds. This includes C–C(sp), C–C(sp2), and C–C(sp3) single bonds; carbon–carbon double bonds; and carbon–carbon triple bonds, with a focus on catalysis by transition metals or organocatalysts. Additionally, specific topics, such as ring-opening processes involving carbon–carbon bond cleavage in three-, four-, five-, and six-membered rings, are discussed, and exemplar applications of these techniques are showcased in the context of complex bioactive molecules or drug discovery. This review aims to shed light on recent advancements in the field and propose potential avenues for future research in the realm of late-stage carbon–carbon bond functionalization.
We report a three-component olefin reductive dicarbofunctionalization for constructing alkylborates, specifically, nickel-catalyzed reductive dialkylation and alkylarylation of vinyl boronates with a ...variety of alkyl bromides and aryl iodides. This reaction exhibits good coupling efficiency and excellent functional group compatibility, providing convenient access to the late-stage modification of complex natural products and drug molecules. Combined with alkylborate transformations, this reaction could also find applications in the modular and convergent synthesis of complex compounds.
Nickel-catalyzed three-component olefin reductive dicarbofunctionalization for constructing alkylborates was achieved.
Transition-metal-catalyzed direct site-selective functionalization of arene C-H bonds has emerged as an innovative approach for building the core structure of pharmaceutical agents and other ...versatile complex compounds. However, para-selective C-H functionalization has seldom been explored, only a few examples, such as steric-hindered arenes, electron-rich arenes, and substrates with a directing group, have been reported to date. Here we describe the development of a ruthenium-enabled para-selective C-H difluoromethylation of anilides, indolines, and tetrahydroquinolines. This reaction tolerates various substituted arenes, affording para-difluoromethylation products in moderate to good yields. Results of a preliminary study of the mechanism indicate that chelation-assisted cycloruthenation might play a role in the selective activation of para-C
-H bonds. Furthermore, this method provides a direct approach for the synthesis of fluorinated drug derivatives, which has important application for drug discovery and development.
The preparation of nickel nanoparticles as efficient reductive amination catalysts by pyrolysis of in situ generated Ni‐tartaric acid complex on silica is presented. The resulting stable and reusable ...Ni‐nanocatalyst enables the synthesis of functionalized and structurally diverse primary benzylic, heterocyclic and aliphatic amines starting from inexpensive and readily available carbonyl compounds and ammonia in presence of molecular hydrogen. Applying this Ni‐based amination protocol, ‐NH2 moiety can be introduced in structurally complex compounds, for example, steroid derivatives and pharmaceuticals.
Tartaric acid‐derived Ni‐nanoparticles: Pyrolysis of Ni‐tartaric acid on silica produces stable and reusable nickel nanoparticles, which empowers the synthesis of linear and branched benzylic, heterocyclic, and aliphatic amines from easily accessible and inexpensive carbonyl compounds and ammonia using molecular hydrogen.
Abstract
Plant-sourced aromatic amino acid (AAA) derivatives are a vast group of compounds with broad applications. Here, we present the development of a yeast consortium for efficient production of ...(
S
)-norcoclaurine, the key precursor for benzylisoquinoline alkaloid biosynthesis. A xylose transporter enables the concurrent mixed-sugar utilization in
Scheffersomyces stipitis
, which plays a crucial role in enhancing the flux entering the highly regulated shikimate pathway located upstream of AAA biosynthesis. Two quinate permeases isolated from
Aspergillus niger
facilitates shikimate translocation to the co-cultured
Saccharomyces cerevisiae
that converts shikimate to (
S
)-norcoclaurine, resulting in the maximal titer (11.5 mg/L), nearly 110-fold higher than the titer reported for an
S. cerevisiae
monoculture. Our findings magnify the potential of microbial consortium platforms for the economical de novo synthesis of complex compounds, where pathway modularization and compartmentalization in distinct specialty strains enable effective fine-tuning of long biosynthetic pathways and diminish intermediate buildup, thereby leading to increases in production.
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