Reaction of Aromatic N-Oxides with Dipolarophiles. IX. Formation of 1:2 Cycloadduct of 2-Alkylpyridine N-Oxides and Phenyl Isocyanates and a Frontier Molecular Orbital Study
A series of 1:2 cycloadducts of a new type was obtained from the reaction of 2-alkylpyridine N-oxides with phenyl isocyanates.The reaction mechanism are discussed in terms of frontier molecular orbital theory based on CNDO/2 and MINDO/2 calculations and kinetic data.The small solvent effect and activation parameters (Ea=14 kcal/mol, ΔS=-46 e.u.) observed for the reaction of 2-alkylpyridine N-oxides with phenyl isocyanates indicate that the cycloaddition proceeds via concerted pathways involving little charge separation in the transition state.Keywords - 1,3-dipolar cycloaddition; 2-alkylpyridine N-oxide; phenyl isocyanate; kinetics; frontier molecular orbital; 1:2 cycloadduct; solvent effect; sigmatropic rearrangement
Get Best Price for106411-66-9N-(4-Chloro-phenyl)-2-[(3aS,7aS)-3-(4-chloro-phenyl)-6-methyl-2-oxo-2,3,3a,7a-tetrahydro-4H-oxazolo[4,5-b]pyridin-(5Z)-ylidene]-acetamide