Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Development of a mild and versatile directed cycloaddition approach to pyridines.

ABSTRACT: The aza-Diels-Alder cycloaddition of 1,2,4-triazines with alkynes offers a rapid and convenient method for the synthesis of highly substituted pyridines, but often requires harsh conditions and long reaction times. The present study offers a solution to these limitations by use of a temporary tether established by a Lewis acid-base complexation of in situ generated alkynylboranes and triazines bearing a Lewis basic donor. The cycloaddition reactions take place within 20?min at 40?°C and provide direct access to a broad range of pyridines with complete and predictable regiocontrol. The carbon?boron bond can be further functionalised by cross-coupling allowing further functionality to be introduced after cycloaddition.

SUBMITTER: Bachollet SP

PROVIDER: S-EPMC4313684 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Development of a mild and versatile directed cycloaddition approach to pyridines.

Bachollet Sylvestre P J T SP Vivat Jérôme F JF Cocker Dean C DC Adams Harry H Harrity Joseph P A JP

Chemistry (Weinheim an der Bergstrasse, Germany) 20140821 40

The aza-Diels-Alder cycloaddition of 1,2,4-triazines with alkynes offers a rapid and convenient method for the synthesis of highly substituted pyridines, but often requires harsh conditions and long reaction times. The present study offers a solution to these limitations by use of a temporary tether established by a Lewis acid-base complexation of in situ generated alkynylboranes and triazines bearing a Lewis basic donor. The cycloaddition reactions take place within 20 min at 40 °C and provide ...[more]

PMID: 25145488

Similar Datasets

A Merged Aldol Condensation, Alkene Isomerization, Cycloaddition/Cycloreversion Sequence Employing Oxazinone Intermediates for the Synthesis of Substituted Pyridines.

Project description:A domino reaction sequence has been evaluated that begins with union of novel dihydrooxazinone precursors with 2-alkynyl-substituted benzaldehyde components through aldol condensation. Ensuing operations, including alkene isomerization, Diels-Alder, and retrograde Diels-Alder with loss of CO2 occurs in the same reaction vessel to provide polysubstituted tricyclic pyridine products.

| S-EPMC5791744 | biostudies-literature

An alternative approach to produce versatile retinal organoids with accelerated ganglion cell development.

Project description:Genetically complex ocular neuropathies, such as glaucoma, are a major cause of visual impairment worldwide. There is a growing need to generate suitable human representative in vitro and in vivo models, as there is no effective treatment available once damage has occured. Retinal organoids are increasingly being used for experimental gene therapy, stem cell replacement therapy and small molecule therapy. There are multiple protocols for the development of retinal organoids available, however, one potential drawback of the current methods is that the organoids can take between 6 weeks and 12 months on average to develop and mature, depending on the specific cell type wanted. Here, we describe and characterise a protocol focused on the generation of retinal ganglion cells within an accelerated four week timeframe without any external small molecules or growth factors. Subsequent long term cultures yield fully differentiated organoids displaying all major retinal cell types. RPE, Horizontal, Amacrine and Photoreceptors cells were generated using external factors to maintain lamination.

| S-EPMC7806597 | biostudies-literature

Lewis base directed cycloaddition reactions of 2-pyrones and alkynylaluminum reagents.

Project description:In situ generated alkynylaluminum reagents have been utilized in a [4 + 2] cycloaddition with 2-pyrones bearing a Lewis basic donor. The reactions proceed at or below room temperature and with complete regiocontrol. This one-pot method affords diversely substituted aromatic compounds under very mild conditions.

| S-EPMC3766945 | biostudies-literature

The discovery of [Ni(NHC)RCN]2 species and their role as cycloaddition catalysts for the formation of pyridines.

Project description:The reaction of Ni(COD)(2), IPr, and nitrile affords dimeric [Ni(IPr)RCN](2) in high yields. X-ray analysis revealed these species display simultaneous ?(1)- and ?(2)-nitrile binding modes. These dimers are catalytically competent in the formation of pyridines from the cycloaddition of diynes and nitriles. Kinetic analysis showed the reaction to be first order in [Ni(IPr)RCN](2), zeroth order in added IPr, zeroth order in nitrile, and zeroth order in diyne. Extensive stoichiometric competition studies were performed, and selective incorporation of the exogenous, not dimer bound, nitrile was observed. Post cycloaddition, the dimeric state was found to be largely preserved. Nitrile and ligand exchange experiments were performed and found to be inoperative in the catalytic cycle. These observations suggest a mechanism whereby the catalyst is activated by partial dimer-opening followed by binding of exogenous nitrile and subsequent oxidative heterocoupling.

| S-EPMC3480329 | biostudies-literature

Highly-efficient and versatile fluorous-tagged Cu(I)-catalyzed azide-alkyne cycloaddition ligand for preparing bioconjugates.

Project description:A novel ligand (FBTTBE) for Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) has been developed, which demonstrates not only superior catalytic efficiency but also the ease of removing toxic copper species. FBTTBE has also been successfully applied in the synthesis of radiometal-labeled peptide and antibody without observable transchelation with the non-radioactive Cu(i) catalyst.

| S-EPMC4654650 | biostudies-other

New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines.

Project description:An efficient and operationally simple synthesis of 7-deuteropyrazolo[1,5-a]pyridine and 7-deutero-1,2,4-triazolo[1,5-a]pyridine derivatives using α-H/D exchange of 1-aminopyridinium cations in basic D2O followed by a 1,3-cycloaddition of acetylenes and nitriles is presented. A high regioselectivity and a high degree of deuterium incorporation were achieved. The procedure was applied for several 4-R-1-aminopyridinium cations (R = H, Me, OMe).

| S-EPMC5433178 | biostudies-literature

Development of a ligand-directed approach to study the pathogenesis of invasive aspergillosis.

Project description:Invasive aspergillosis is a leading cause of infectious death in immunosuppressed patients. Here, we adapted a phage display library-based selection to screen and identify binding peptides to the surface of Aspergillus fumigatus conidia and hyphae. We identified a peptide (sequence CGGRLGPFC) that reliably binds to the surface of Aspergillus fumigatus hyphae. Binding was not Aspergillus strain specific, as it was also observed in hyphae of other Aspergillus clinical isolates. Furthermore, CGGRLGPFC-displaying phage targets Aspergillus fumigatus hyphae on formalin-fixed paraffin-embedded histopathology sections of lung tissue recovered from mice with invasive pulmonary aspergillosis. This approach may yield reagents such as peptidomimetics for novel diagnostic and therapeutic interventions in invasive aspergillosis.

| S-EPMC1273901 | biostudies-literature

Target-Directed Azide-Alkyne Cycloaddition for Assembling HIV-1 TAR RNA Binding Ligands.

Project description:The highly conserved HIV-1 transactivation response element (TAR) binds to the trans-activator protein Tat and facilitates viral replication in its latent state. The inhibition of Tat-TAR interactions by selectively targeting TAR RNA has been used as a strategy to develop potent antiviral agents. Therefore, HIV-1 TAR RNA represents a paradigmatic system for therapeutic intervention. Herein, we have employed biotin-tagged TAR RNA to assemble its own ligands from a pool of reactive azide and alkyne building blocks. To identify the binding sites and selectivity of the ligands, the in situ cycloaddition has been further performed using control nucleotide (TAR DNA and TAR RNA without bulge) templates. The hit triazole-linked thiazole peptidomimetic products have been isolated from the biotin-tagged target templates using streptavidin beads. The major triazole lead generated by the TAR RNA presumably binds in the bulge region, shows specificity for TAR RNA over TAR DNA, and inhibits Tat-TAR interactions.

| S-EPMC7687225 | biostudies-literature

Cyano Diels-Alder and cyano ene reactions. Applications in a formal [2 + 2 + 2] cycloaddition strategy for the synthesis of pyridines.

Project description:Two metal-free, formal [2 + 2 + 2] cycloaddition strategies for the construction of polycyclic pyridine derivatives are described that proceed via pericyclic cascade mechanisms featuring the participation of unactivated cyano groups as enophile and dienophile cycloaddition partners.

| S-EPMC2944912 | biostudies-literature

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines.

Project description:The imidazo[1,2-a]pyridine moiety is present in drugs with several biological activities. The most direct way of obtaining this nucleus is the Groebke-Blackburn-Bienaymé three-component reaction (GBB-3CR) between aminopyridines, aldehydes, and isocyanides under both Lewis and Brønsted acid catalysis. However, several catalysts for this reaction have major drawbacks such as being expensive, extremely dangerous, strong oxidizing, and even explosive. In this scenario, heteropolyacids emerge as greener and safer alternatives due to their very strong Brønsted acidity. In particular, phosphotungstic acid (HPW) is an economical and green attractive catalyst for being cheap, non-toxic, and is known for its chemical and thermal stability. Herein, we report a straightforward approach to the GBB-3CR using HPW as catalyst in ethanol under microwave (μw) heating. This convenient environmentally benign methodology is broad in scope, provides the heterobicyclic products in high yields (up to 99%), with a low catalyst loading (2 mol %) in only 30 minutes, and allows the successful use of aliphatic aldehydes, substrates not so frequently explored with most usual catalysts for this reaction. Furthermore, the aforementioned advantages make this methodology very attractive and superior to the existing ones.

| S-EPMC10964034 | 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