Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

In situ generation of N-unsubstituted imines from alkyl azides and their applications for imine transfer via copper catalysis.

ABSTRACT: Although azides have been widely used in nitrene transfer reactions, in situ generation of N-H imines from azides for downstream transformations has rarely been explored. We report copper-mediated formation of N-unsubstituted aliphatic imines from easily available aliphatic azides using a customized phenanthroline-based ligand (L1*). Through trapping in situ-generated N-H imines, multisubstituted pyridines or indoles were readily synthesized. 13C-labeled azide was used as part of an isotope labeling study, which suggests that the construction of pyridine derivatives involves a three-component dehydrogenative condensation. The construction of 2,3,5-triaryl pyridines using this method provided evidence supporting a proposed pathway involving both imine formation and abnormal Chichibabin pyridine synthesis. The generation of N-unsubstituted imine intermediates was also confirmed by formation of indole derivatives from alkyl azides.

SUBMITTER: Hu L

PROVIDER: S-EPMC5550227 | biostudies-other | 2017 Aug

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

In Situ Generation of Fluorescent Copper Nanoclusters Embedded in Monolithic Eggshell Membrane: Properties and Applications.

Project description:Luminescent metal nanoclusters have attracted considerable research attention in recent years due to their unique properties and extensive usage in many fields. Three different synthetic routes were developed to in situ generate orange and red emitting copper nanoclusters embedded in monolithic eggshell membrane (Cu NCs@ESM) using different reducing reagents including N₂H₄·H₂O, NH₂OH·HCl and Vitamin C at room temperature for the first time. The routes are extremely facile, low-cost and versatile. The obtained Cu NCs@ESM nanocomposites exhibit excellent photostability and chemical stability, laying the foundation for various practical applications. Fluorescent surface patterning was demonstrated based on the proposed strategy easily. Significantly, the Cu NCs@ESM shows selective fluorescence quenching response to Hg2+ ions and good catalytic activity for methylene blue (MB) reduction degradation making it ideal as portable sensing strip and recyclable catalyst. The work provides a general strategy for the fabrication of other various monolithic nanomaterials with potential applications.

| S-EPMC6213854 | biostudies-literature

The Effect of Alkyl Substitution of Novel Imines on Their Supramolecular Organization, towards Photovoltaic Applications.

Project description:Three novel conjugated polyazomethines have been obtained by polycondensation of diamines consisting of the diimine system, with either 2,5-bis(octyloxy)terephthalaldehyde or 9-(2-ethylhexyl)carbazole-3,6-dicarboxaldehyde. Partial replacement of bulky solubilizing substituents with the smaller side groups has allowed to investigate the effect of supramolecular organization. All obtained compounds have been subsequently identified using the NMR and FTIR spectroscopies and characterized by the thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, UV-Vis spectroscopy, and X-ray diffraction. Investigated polymers have shown a good thermal stability and high glass transition temperatures. X-ray measurements have proven that partial replacement of octyloxy side chains with smaller methoxy groups induced a better planarization of macromolecule. Such modification has tuned the LUMO level of this molecule and caused a bathochromic shift of the lowest energy absorption band. On the contrary, imines consisting of N-ethylhexyl substituted carbazole units have not been so clearly affected by alkyl chain length modification. Photovoltaic activity of imines (acting as a donor) in bulk-heterojunction systems has been observed for almost all studied compounds, blended with the fullerene derivative (PCBM) in various weight ratios.

| S-EPMC8036393 | biostudies-literature

Tackling N-Alkyl Imines with 3d Metal Catalysis: Highly Enantioselective Iron-Catalyzed Synthesis of α-Chiral Amines.

Project description:A readily activated iron alkyl precatalyst effectively catalyzes the highly enantioselective hydroboration of N-alkyl imines. Employing a chiral bis(oxazolinylmethylidene)isoindoline pincer ligand, the asymmetric reduction of various acyclic N-alkyl imines provided the corresponding α-chiral amines in excellent yields and with up to >99 % ee. The applicability of this base metal catalytic system was further demonstrated with the synthesis of the pharmaceuticals Fendiline and Tecalcet.

| S-EPMC7539954 | biostudies-literature

Intramolecular Csp<sup>3</sup>-H/C-C bond amination of alkyl azides for the selective synthesis of cyclic imines and tertiary amines.

Project description:The intramolecular Csp3-H and/or C-C bond amination is very important in modern organic synthesis due to its efficiency in the construction of diversified N-heterocycles. Herein, we report a novel intramolecular cyclization of alkyl azides for the synthesis of cyclic imines and tertiary amines through selective Csp3-H and/or C-C bond cleavage. Two C-N single bonds or a C[double bond, length as m-dash]N double bond are efficiently constructed in these transformations. The carbocation mechanism differs from the reported metal nitrene intermediates and therefore enables metal-free and new transformation.

| S-EPMC8159442 | biostudies-literature

Copper-Catalyzed Addition of Grignard Reagents to in situ Generated Indole-Derived Vinylogous Imines.

Project description:Chiral indole derivatives are ubiquitous motifs in pharmaceuticals and alkaloids. Herein, the first protocol for catalytic asymmetric conjugate addition of Grignard reagents to various sulfonyl indoles, offering a straightforward approach for the synthesis of chiral 3-sec-alkyl-substituted indoles in high yields and enantiomeric ratios is presented. This methodology makes use of a chiral catalyst based on copper phosphoramidite complexes and in situ formation of vinylogous imine intermediates.

| S-EPMC7918645 | biostudies-literature

An (R)-Imine Reductase Biocatalyst for the Asymmetric Reduction of Cyclic Imines.

Project description:Although the range of biocatalysts available for the synthesis of enantiomerically pure chiral amines continues to expand, few existing methods provide access to secondary amines. To address this shortcoming, we have over-expressed the gene for an (R)-imine reductase [(R)-IRED] from Streptomyces sp. GF3587 in Escherichia coli to create a recombinant whole-cell biocatalyst for the asymmetric reduction of prochiral imines. The (R)-IRED was screened against a panel of cyclic imines and two iminium ions and was shown to possess high catalytic activity and enantioselectivity. Preparative-scale synthesis of the alkaloid (R)-coniine (90?% yield; 99?% ee) from the imine precursor was performed on a gram-scale. A homology model of the enzyme active site, based on the structure of a closely related (R)-IRED from Streptomyces kanamyceticus, was constructed and used to identify potential amino acids as targets for mutagenesis.

| S-EPMC4973613 | biostudies-literature

Unexpected in-situ Free Radical Generation and Catalysis to Ag/Polymer Nanocomposite.

Project description:In this study, we discover unexpectedly that simple reaction of AgNO3 with oleic acid (OA) without solvent and surfactant could generate alkyl free radical which can catalyze double-bond polymerization of OA to form 1D polymeric oleic acid (POA) chain. In certain conditions, these POA chains circumvolute tightly each other to form microspheres and micro-plates in which monodisperse 4-5 nm Ag nanoparticles (NPs) were absorbed. It has been revealed that alkyl free radical generated during the redox reaction of carboxyl group of OA with Ag(+) at relative low temperature. Then, the alkyl free radical catalyzed the double-bond polymerization of OA when the reaction temperature was further increased. Different from commonly-seen hydrophobic nanoparticles prepared in oleic acid-based microemulsion system, the nanocomposites cannot dispersed in n-hexane and could dispersed in ethanol and THF. The unusual dispersion behavior has been explained in terms of their structure and polarity of POA chain. The method combines the nucleation of Ag nanoparticles and the polymerization of monomer in a facile one-pot reaction, which provides a novel way for metal-polymer microsphere nanocomposite with low-cost, easy-operation and high-yield.

| S-EPMC4498183 | biostudies-literature

Enantioselective Generation of Adjacent Stereocenters in a Copper-Catalyzed Three-Component Coupling of Imines, Allenes, and Diboranes.

Project description:A highly enantio- and diastereoselective copper-catalyzed three-component coupling affords the first general synthesis of homoallylic amines bearing adjacent stereocenters from achiral starting materials. The method utilizes a commercially available NHC ligand and copper source, operates at ambient temperature, couples readily available simple imines, allenes, and diboranes, and yields high-value homoallylic amines that exhibit versatile amino, alkenyl, and boryl units.

| S-EPMC5103189 | biostudies-literature

Aldehyde and Ketone Synthesis by P450-Catalyzed Oxidative Deamination of Alkyl Azides.

Project description:Heme-containing proteins have recently attracted increasing attention for their ability to promote synthetically valuable transformations not found in nature. Following the recent discovery that engineered variants of myoglobin can catalyze the direct conversion of organic azides to aldehydes, we investigated the azide oxidative deamination reactivity of a variety of hemoproteins featuring different heme coordination environments. Our studies show that although several heme-containing enzymes possess basal activity in this reaction, an engineered variant of the bacterial cytochrome P450 CYP102A1 constitutes a particularly efficient biocatalyst for promoting this transformation, exhibiting a broad substrate scope along with high catalytic activity (up to 11,300 TON), excellent chemoselectivity, and enhanced reactivity toward secondary alkyl azides to yield ketones. Mechanistic studies and Michaelis-Menten analyses provided insights into the mechanism of the reaction and the impact of active site mutations on the catalytic properties of the P450. Altogether, these studies demonstrate that engineered P450 variants represent promising biocatalysts for the synthesis of aryl aldehydes and ketones via the oxidative deamination of alkyl azides under mild reaction conditions.

| S-EPMC5111867 | biostudies-literature

<i>Ortho</i>-Phosphinoarenesulfonamide-Mediated Staudinger Reduction of Aryl and Alkyl Azides.

Project description:Conventional Staudinger reductions of organic azides are sluggish with aryl or bulky aliphatic azides. In addition, Staudinger reduction usually requires a large excess of water to promote the decomposition of the aza-ylide intermediate into phosphine oxide and amine products. To overcome the challenges above, we designed a novel triaryl phosphine reagent 2c with an ortho-SO2NH2 substituent. Herein, we report that such phosphine reagents are able to mediate the Staudinger reduction of both aryl and alkyl azides in either anhydrous or wet solvents. Good to excellent yields were obtained in all cases (even at a diluted concentration of 0.01 M). The formation of B-TAP, a cyclic aza-ylide, instead of phosphine oxide, eliminates the requirement of water in the Staudinger reduction. In addition, computational studies disclose that the intramolecular protonation of the aza-ylide by the ortho-SO2NH2 group is kinetically favorable and responsible for the acceleration of Staudinger reduction of the aryl azides.

| S-EPMC9458194 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data