Browse
Submit Data
Databases
API
Help

Dataset Information

18 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Alkyne Cycloadditions Mediated by Tetrabutylammonium Fluoride: A Unified and Diversifiable Route to Isoxazolines and Pyrazolines.

ABSTRACT: A versatile approach to isoxazolines and pyrazolines by the cyclization of alkyne substrates using tetrabutylammonium fluoride (TBAF) is described. The reported diheteroatom cycles were produced under mild reaction conditions and with broad product scope. Evidence is also provided for a vinyl anion intermediate produced under unusually mild conditions, which was trapped in situ as part of a tandem cyclization/aldehyde addition sequence. Finally, a deprotection/functionalization method is described, leading to a substituted pyrazoline in good diastereoselectivity.

SUBMITTER: Nagy E

PROVIDER: S-EPMC6457990 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Alkyne Cycloadditions Mediated by Tetrabutylammonium Fluoride: A Unified and Diversifiable Route to Isoxazolines and Pyrazolines.

Nagy Edith E Lepore Salvatore D SD

Organic letters 20170706 14

A versatile approach to isoxazolines and pyrazolines by the cyclization of alkyne substrates using tetrabutylammonium fluoride (TBAF) is described. The reported diheteroatom cycles were produced under mild reaction conditions and with broad product scope. Evidence is also provided for a vinyl anion intermediate produced under unusually mild conditions, which was trapped in situ as part of a tandem cyclization/aldehyde addition sequence. Finally, a deprotection/functionalization method is describ ...[more]

PMID: 28682079

Similar Datasets

Synthesis and antifungal activity of novel pyrazolines and isoxazolines derived from cuminaldehyde.

Project description:Two series of novel cuminaldehyde derivatives containing pyrazoline and isoxazoline moieties have been designed and synthesized. All of the compounds were characterized via 1H-NMR,13C-NMR, and HRMS. The antifungal activities were evaluated against six plant-pathogenic fungi. 3-(2-Fluorophenyl)-5-(4-isopropylphenyl) isoxazoline (2d) and 1-acetyl-3-(2-fluorophenyl)-5-(4-isopropylphenyl)-2-pyrazoline (3d) displayed higher antifungal activities than commercial fungicides against Sclerotinia sclerotiorum, Physalospora piricola and Pyricularia oryzae. The title compounds (2d and 3d) with strong antifungal activities are worth being further evaluated in vivo and in the field.

| S-EPMC6718356 | biostudies-literature

Highly ?-selective hydrolysis of ?,?-epoxyalcohols using tetrabutylammonium fluoride.

Project description:We report a simple method for the highly regio- and stereoselective hydrolysis of ?,?-epoxyalcohols. Treatment of enantiopure epoxyalcohols derived from Sharpless epoxidation with TBAF/H(2)O resulted in exclusive ring opening at the normally disfavored ?-position, providing access to arabino- or lyxo-configured triols with full preservation of stereochemical purity. The method was applied in syntheses of 5-deoxy-l-arabinose (26) and a family of bicyclic acetals based on the insect pheromone hydroxybrevicomin (4).

| S-EPMC2937070 | biostudies-literature

Fluorogenic Strain-Promoted Alkyne-Diazo Cycloadditions.

Project description:Fluorogenic reactions, in which non- or weakly fluorescent reagents produce highly fluorescent products, are attractive for detecting a broad range of compounds in the fields of bioconjugation and material sciences. Herein, we report that a dibenzocyclooctyne derivative modified with a cyclopropenone moiety (Fl-DIBO) can undergo fast strain-promoted cycloaddition reactions under catalyst-free conditions with azides, nitrones, nitrile oxides, as well as mono- and disubstituted diazo-derivatives. Although the reaction with nitrile oxides, nitrones, and disubstituted diazo compounds gave cycloadducts with low quantum yield, monosubstituted diazo reagents produced 1H-pyrazole derivatives that exhibited an approximately 160-fold fluorescence enhancement over Fl-DIBO combined with a greater than 10,000-fold increase in brightness. Concluding from quantum chemical calculations, fluorescence quenching of 3H-pyrazoles, which are formed by reaction with disubstituted diazo-derivatives, is likely due to the presence of energetically low-lying (n,?*) states. The fluorogenic probe Fl-DIBO was successfully employed for the labeling of diazo-tagged proteins without detectable background signal. Diazo-derivatives are emerging as attractive reporters for the labeling of biomolecules, and the studies presented herein demonstrate that Fl-DIBO can be employed for visualizing such biomolecules without the need for probe washout.

| S-EPMC4712747 | biostudies-literature

Efficient protiodesilylation of unactivated C(sp3)-SiMe2Ph bonds using tetrabutylammonium fluoride.

Project description:[reaction: see text] The protiodesilylation of unactivated C(sp3)-SiMe2Ph bonds proceeds efficiently by treatment with tetrabutylammonium fluoride in wet DMF or THF via isolable dimethylsilanol intermediates.

| S-EPMC2515625 | biostudies-literature

Electrochemical Fluorination and Radiofluorination of Methyl(phenylthio)acetate Using Tetrabutylammonium Fluoride (TBAF).

Project description:Electrochemical fluorination of methyl(phenylthio)acetate was achieved using tetrabutylammonium fluoride (TBAF). Electrochemical fluorination was performed under potentiostatic anodic oxidation using an undivided cell in acetonitrile containing TBAF and triflic acid. The influence of several parameters including: oxidation potential, time, temperature, sonication, TBAF concentration and triflic acid concentration on fluorination efficiency were studied. It was found that the triflic acid to TBAF concentration ratio plays a key role in the fluorination efficiency. Electrochemical fluorination resulted in formation of mono-fluorinated methyl 2-fluoro-2-(phenylthio)acetate verified by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) Spectroscopy. Under optimum conditions 44 ± 3% mono fluorination yield was obtained after a 30 min electrolysis. Electrochemical radiofluorination for the synthesis of methyl 2-[18F]fluoro-2-(phenothio) acetate was also achieved with the same optimized electrochemical cell parameters where TBAF was first passed through an anion exchange resin containing fluorine-18. A radiochemical fluorination efficiency of 7 ± 1% was achieved after 30 min of electrolysis.

| S-EPMC5589193 | biostudies-literature

Chemoselectivity of Tertiary Azides in Strain-Promoted Alkyne-Azide Cycloadditions.

Project description:The strain-promoted alkyne-azide cycloaddition (SPAAC) is the most commonly employed bioorthogonal reaction with applications in a broad range of fields. Over the years, several different cyclooctyne derivatives have been developed and investigated in regard to their reactivity in SPAAC reactions with azides. However, only a few studies examined the influence of structurally diverse azides on reaction kinetics. Herein, we report our investigations of the reactivity of primary, secondary, and tertiary azides with the cyclooctynes BCN and ADIBO applying experimental and computational methods. All azides show similar reaction rates with the sterically non-demanding cyclooctyne BCN. However, due to the increased steric demand of the dibenzocyclooctyne ADIBO, the reactivity of tertiary azides drops by several orders of magnitude in comparison to primary and secondary azides. We show that this chemoselective behavior of tertiary azides can be exploited to achieve semiorthogonal dual-labeling without the need for any catalyst using SPAAC exclusively.

| S-EPMC6391941 | biostudies-literature

A Unified Continuous Flow Assembly-Line Synthesis of Highly Substituted Pyrazoles and Pyrazolines.

Project description:A rapid and modular continuous flow synthesis of highly functionalized fluorinated pyrazoles and pyrazolines has been developed. Flowing fluorinated amines through sequential reactor coils mediates diazoalkane formation and [3+2] cycloaddition to generate more than 30 azoles in a telescoped fashion. Pyrazole cores are then sequentially modified through additional reactor modules performing N-alkylation and arylation, deprotection, and amidation to install broad molecular diversity in short order. Continuous flow synthesis enables the safe handling of diazoalkanes at elevated temperatures, and the use of aryl alkyne dipolarphiles under catalyst-free conditions. This assembly-line synthesis provides a flexible approach for the synthesis of agrochemicals and pharmaceuticals, as demonstrated by a four-step, telescoped synthesis of measles therapeutic, AS-136A, in a total residence time of 31.7 min (1.76 g h-1 ).

| S-EPMC6990874 | biostudies-literature

Surface modification of polymeric micelles by strain-promoted alkyne-azide cycloadditions.

Project description:Organomicelles modified by surface dibenzylcyclooctyne moieties can conveniently be functionalized by strain-promoted alkyne-azide cycloadditions. The ligation approach is highly efficient, does not require toxic reagents and is compatible with a wide variety of functional modules. Interactions of proteins with surface ligands of the micelles have been studied by AFM, which revealed that it leads to disassembly of the particles thereby providing a mechanism for triggered drug release.

| S-EPMC3059085 | biostudies-literature

Investigation of copper-free alkyne/azide 1,3-dipolar cycloadditions using microwave irradiation.

Project description:The prevalence of 1,3-dipolar cycloadditions of azides and alkynes within both biology and chemistry highlights the utility of these reactions. However, the use of a copper catalyst can be prohibitive to some applications. Consequently, we have optimized a copper-free microwave-assisted reaction to alleviate the necessity for the copper catalyst. A small array of triazoles was prepared to examine the scope of this approach, and the methodology was translated to a protein context through the use of unnatural amino acids to demonstrate one of the first microwave-mediated bioconjugations involving a full length protein.

| S-EPMC5761740 | biostudies-literature

Green Methodologies for Copper(I)-Catalyzed Azide-Alkyne Cycloadditions: A Comparative Study.

Project description:Successful copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions may be achieved by several methods. In this paper, four synthetic protocols were performed for direct comparison of time required for the synthesis, yield, and purity of the 1H-1,2,3-triazole products. The methods with Cu(I) catalysts were conventional, microwave heating, solvent-free, and a method using glycerol solvent. The compounds synthesized in this paper were known non-fluorinated triazoles and new fluorinated triazoles. The results lead to the conclusion that the microwave method should be strongly considered for CuAAC syntheses.

| S-EPMC6429464 | 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