Results 11 to 20 of about 57,923 (191)

Intramolecular Azide to Alkene Cycloadditions for the Construction of Pyrrolobenzodiazepines and Azetidino-Benzodiazepines [PDF]

open access: yesMolecules, 2014
The coupling of proline- and azetidinone-substituted alkenes to 2-azidobenzoic and 2-azidobenzenesulfonic acid gives precursors that undergo intramolecular azide to alkene 1,3-dipolar cycloadditions to give imine-, triazoline- or aziridine-containing ...
Karl Hemming   +3 more
doaj   +2 more sources

Highly Regio- and Stereoselective Intramolecular 1,3-Dipolar Cycloadditions of Norbornadiene-Tethered Nitrile Oxides

open access: yes, 2016
Intramolecular cycloadditions with high regio- and stereocontrol are important methods for the efficient assembly of complex molecular structures. Efficient routes to the synthesis of norbornadiene-tethered nitrile oxides have been developed, and their ...
Robert Jordan (346146)   +3 more
core   +18 more sources

Intermolecular 1,3-dipolar cycloadditions of azomethine imines [PDF]

open access: yesARKIVOC, 2006
Dipolar cycloadditions of azomethine imines, formed in situ from aldehydes and N1-alkyl-N2-acylhydrazines, with electron-deficient dipolarophiles produce pyrazolidines: mono-substituted dipolarophiles afford principally 4-substituted ...
Raymond C. F. Jones   +2 more
doaj   +2 more sources

Sydnone-Based Approach to Heterohelicenes through 1,3-Dipolar-Cycloadditions. [PDF]

open access: yesJ Am Chem Soc, 2019
International audienceThe first approach to pyrazole containing helicenes via sydnone-aryne [3+2]-cycloaddition is described. An unprecedented regioselectivity in the cycloaddition step towards the more sterically constrained product was observed in ...
Yen-Pon E   +10 more
europepmc   +2 more sources

Intermolecular 1,3-dipolar cycloadditions of azomethine imines [PDF]

open access: yes, 2007
Dipolar cycloadditions of azomethine imines, formed in situ from aldehydes and N1-alkyl-N2- acylhydrazines, with electron-deficient dipolarophiles produce pyrazolidines: mono-substituted dipolarophiles afford principally 4-substituted ...
Ray Jones (1249197)   +2 more
core   +6 more sources

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

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

open access: yesAngew Chem Int Ed Engl
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 ...
Schulz J   +7 more
europepmc   +3 more sources

Kinetic solvent effects on 1,3-dipolar cycloadditions of benzonitrile oxide [PDF]

open access: yes, 2005
The kinetics of 1,3-dipolar cycloadditions of benzonitrile oxide with a series of N-substituted maleimides and with cyclopentene are reported for water, a wide range of organic solvents and binary solvent mixtures.
Jan B. F. N. Engberts   +5 more
core   +2 more sources

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

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