Results 11 to 20 of about 27,886 (261)

Activation of Dinitrogen as A Dipolarophile in 1,3-Dipolar Cycloadditions: A Theoretical Study Using Nitrile Imines as “Octet” 1,3-Dipoles [PDF]

open access: yesScientific Reports, 2017
Theoretical calculations at the G4MP2 level of theory demonstrate that it is possible to activate dinitrogen to make it react in dipolar cycloadditions using neutral beryllium derivatives and other neutral metallic compounds.
M. Merced Montero-Campillo   +2 more
doaj   +4 more sources

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

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

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   +3 more sources

Decarboxylation-Driven Double Annulations: Innovative Multi-Component Reaction Pathways [PDF]

open access: yesMolecules
A concerted five-component reaction strategy has been developed, featuring double [3+2] cycloadditions utilizing aspartic acid. This approach provides valuable insights into mechanistic pathways, allowing for the distinction between concerted and ...
Desheng Zhan   +4 more
doaj   +2 more sources

Decarboxylative 1,3-dipolar cycloadditions of l-proline. [PDF]

open access: yesRSC Adv
l-Proline is widely used in 1,3-dipolar cycloaddition reactions. Azomethine ylide derived from decarboxylative condensation of l-proline and 1,2-dicarbonyl compounds can directly react with various dipolarophiles through 1,3-dipolar cycloaddition.
Doraghi F   +6 more
europepmc   +3 more sources

Decreasing Distortion Energies without Strain: Diazo-Selective 1,3-Dipolar Cycloadditions. [PDF]

open access: yesJ Org Chem, 2016
The diazo group has attributes that complement those of the azido group for applications in chemical biology. Here, we use computational analyses to provide insights into the chemoselectivity of the diazo group in 1,3-dipolar cycloadditions.
Gold B, Aronoff MR, Raines RT.
europepmc   +2 more sources

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions [PDF]

open access: yesBeilstein Journal of Organic Chemistry, 2014
An operationally simple, convenient, and mild strategy for the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed.
Andreas Gansäuer   +5 more
doaj   +2 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 pyrazolidines.
Raymond C. F. Jones   +2 more
doaj   +4 more sources

Synthesis of 2-substituted 9-oxa-guanines {5-aminooxazolo[5,4-d]pyrimidin-7(6H)-ones} and 9-oxa-2-thio-xanthines {5-mercaptooxazolo[5,4-d]pyrimidin-7(6H)-ones} [PDF]

open access: yesBeilstein Journal of Organic Chemistry, 2008
Oxazolo[5,4-d]pyrimidines can be considered as 9-oxa-purine analogs of naturally occurring nucleic acid bases. Interest in this ring system has increased due to recent reports of biologically active derivatives.
Subrata Mandal   +4 more
doaj   +4 more sources

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps [PDF]

open access: yesBeilstein Journal of Organic Chemistry
Pyrazoles are rarely found in nature but are traditionally used in the agrochemical and pharmaceutical industries, while other areas of use are also actively developing. However, they have also found numerous other applications.
Ignaz Betcke   +3 more
doaj   +2 more sources

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