Search results for "3-Dipolar cycloaddition reactions"

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Study of Reactivity in the 1,3-Dipolar Cycloaddition Reactions Leading to New Triazolopyrrolopyrazine Ring Systems

2010

The influence of the structural symmetry of the 2-pi double-reactive-sites component in the 1,3-dipolar cycloaddition reactions, involving nitrilimines as dipoles, was investigated. the experimental data showed that the loss of the symmetry leads to the formation of the monocycloadduct in good yields.

Dipole13-Dipolar Cycloaddition Reactions Triazolopyrrolopyrazine Ring SystemsChemistryOrganic Chemistry13-Dipolar cycloadditionStructural symmetryReactivity (chemistry)Ring (chemistry)PhotochemistrySettore CHIM/08 - Chimica FarmaceuticaSymmetry (physics)CycloadditionSynlett
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The influence of substitution in the quinoxaline nucleus on 1,3-dipolar cycloaddition reactions

2013

The reaction mechanism of 1,3-dipolar cycloadditions of both symmetric and unsymmetric benzo-condensed diazines with a nitrilimine dipole, to give two different mono- and bis-cycloadducts, in tetrahydrofuran (THF) solution, was studied by DFT calculatio ns. The results obtained show that each 1,3-dipolar cycloaddition reaction always proceeds by a two steps mechanism, in which the first intermediate shows only one covalent bond between the beta carbon of the nitrilimine and the aromatic nitrogen of the diazine molecule. The structure and energy content of the two transition states of the two cycloaddition steps, in the case of the unsymmetric benzo-condensed diazine, nicely explains why the…

Settore CHIM/03 - Chimica Generale E InorganicaSettore CHIM/08 - Chimica FarmaceuticaDFT calculations 13-Dipolar cycloaddition reactions Quinoxalines Reaction mechanism
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