54904-01-7Relevant academic research and scientific papers
Reaction of Aromatic N-Oxides with Dipolarophiles. VI. Further Studies on the 1,3-Dipolar Cycloaddition Reaction of Pyridine N-Oxides with Phenyl Isocyanates
Harano, Kazunobu,Suematsu, Fumihiro,Matsuoka, Toshikazu,Hisano, Takuzo
, p. 543 - 552 (2007/10/02)
To provide additional evidence for the concerted mechanism postulated for the 1,3-dipolar cycloaddition reaction of pyridine N-oxides with phenyl isocyanates, kinetic studies on the cycloaddition reactions were conducted in a variety of solvents.The cycloaddition showed low sensitivity to the ionizing power of the medium, indicating that it proceeds by a mechanism which involves very little change in charge separation between the ground state and the transition state.The observed cycloadditivity and site selectivity are discussed in terms of the following controlling factors based on MINDO/3 calculations: HOMO-LUMO control, secondary orbital interaction, steric interaction, dipole-dipole interaction and charge-transfer complexation. Keywords - 1,3-dipolar cycloaddition; pyridine N-oxide; phenyl isocyanate; kinetics; frontier molecular orbital; solvent effect
Reaction of Aromatic N-Oxides with Dipolarophiles. VII. Effect of Aromaticity on 1,3-Dipolar Cycloaddition Reactivity of Substituted Pyridine N-Oxides and Preparation of Oxazolopyridine Derivatives
Matsuoka, Toshikazu,Shinada, Minoru,Suematsu, Fumihiro,Harano, Kazunobu,Hisano, Takuzo
, p. 2077 - 2090 (2007/10/02)
The 1,3-dipolar cycloaddition reactivity of pyridine N-oxides to phenyl isocyanate was calculated by the MINDO/3 MO method using the perturbation equation derived by Klopman and Salem.The calculated did not predict the low reactivity of acceptor substitut
