Results 11 to 20 of about 1,577 (174)

The Azide-Allene Dipolar Cycloaddition: Is DFT Able to Predict Site- and Regio-Selectivity?

open access: yesMolecules, 2021
The site- and regio-selectivity of thermal, uncatalysed 1,3-dipolar cycloadditions between arylazides and mono- or tetra-substituted allenes with different electronic features have been investigated by both conceptual (reactivity indices) and ...
Giorgio Molteni, Alessandro Ponti
doaj   +1 more source

Studies on the [2+3] cycloaddition reaction of nitrile oxides to abietic acid esters [PDF]

open access: yesJournal of the Serbian Chemical Society, 2019
[2+3] Dipolar cycloadditions of aromatic nitrile oxides to abietic acid esters were investigated. The reactions showed complete site selectivity and regioselectivity, while the stereoselectivity depended on the structures of the dipolarophiles.
Gucma Mirosław   +3 more
doaj   +1 more source

Cycloadditions with 2-Chloro-1-Nitroethylene

open access: yesCHIMIA, 1975
2-chloronitroethylene replaces successfully the still elusive unsubstituted nitroacetylene in both the 1,3-dipolar and Diels-Alder cycloadditions. These reactions generally afford interesting nitrated cyclic and heterocyclic compounds.
R. Verbruggen, H.G. Viehe
doaj   +1 more source

Crystal and Molecular Structures of N-benzyl-C-(2-pyridyl) nitrone and its ZnBr2 Complex. A Study of Their Reactivity

open access: yesMolecules, 2001
The ZnBr2 complex of the title compound has been studied by both structural and theoretical methods. Similar reactivities have been observed for the nitrone alone and the complex in 1,3-dipolar cycloadditions and nucleophilic additions.
Tomas Tejero   +5 more
doaj   +1 more source

Intramolecular Cycloaddition of Imines of Cysteine Derivatives

open access: yesMolecules, 1998
Azomethine ylides were generated from Schiffs bases of S-allylcysteine methyl ester and their intramolecular 1,3-dipolar cycloadditions were studied. These reactions led to the synthesis of thieno[3,4-b]pyrrole derivatives in good yield.
Teresa M. V. D. Pinho e Melo   +2 more
doaj   +1 more source

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

open access: yesMolecules, 2016
We provide a comprehensive account of the 1,3-dipolar cycloaddition reactions of azomethine ylides with carbonyl dipolarophiles. Many different azomethine ylides have been studied, including stabilized and non-stabilized ylides.
Adam G. Meyer, John H. Ryan
doaj   +1 more source

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

open access: yesBeilstein Journal of Organic Chemistry, 2021
This work presents an examination of the selective functionalization of norbornadiene through nitrile oxide 1,3-dipolar cycloaddition/ring-opening metathesis (ROM)/cross-metathesis (CM) protocols. Functionalization of commercially available norbornadiene
Zsanett Benke   +2 more
doaj   +1 more source

Arylthio-substituierte Nitrilylide aus der Thermolyse von 4-Arylthio-3-oxazolin-5-onen

open access: yesCHIMIA, 1984
Thermolysis of 4-arylthio- and 4-benzylthio-3-oxazolin-5-ones leads to arylthio- and benzylthio-substituted nitrile ylides, which undergo 1,3-dipolar cycloadditions with reactive dipolarophiles to give 5-membered aza-heterocycles (Schemes 1 and 2).
Peter Wipf, Heinz Heimgartner
doaj   +1 more source

Reaction profiles for quantum chemistry-computed [3 + 2] cycloaddition reactions

open access: yesScientific Data, 2023
Bio-orthogonal click chemistry based on [3 + 2] dipolar cycloadditions has had a profound impact on the field of biochemistry and significant effort has been devoted to identify promising new candidate reactions for this purpose.
Thijs Stuyver   +2 more
doaj   +1 more source

Photo‐Triggered, Fast, and Fluorogenic Thiophene‐Based Cycloalkynes for the Bioorthogonal Fluorescent Labeling of 1,3‐Dipole‐Tagged Molecules in No‐Wash Conditions

open access: yesAngewandte Chemie, EarlyView.
Thiophene is king! The fusion of thiophene rings to cycloalkynes super‐charged their copper‐free click chemistry applications, by (1) enhancing the alkyne reactivity (fastest cyclooctyne to date) and (2) rendering the alkyne fluorogenic (with fluorescence enhancement up to 150‐fold upon reaction), making these bioorthogonal reagents ideal for tracking ...
Jurgen Schulz   +7 more
wiley   +2 more sources

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