Tetrahedron

Conformational equilibria and nitrogen inversion in tetrahydro-1, 2, 5-oxadiazines

FG Riddell, ES Turner

Index: Riddell,F.G.; Turner,E.S. Tetrahedron, 1979 , vol. 35, p. 1311 - 1314

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Citation Number: 4

Abstract

Conformational equilibria and nitrogen inversion barriers in some tetrahydro-1, 2, 5- oxadiazines have been investigated by 1H NMR spectroscopy and by chemical equilibration. The conformational free energy differences obtained are: 4-methyl, 1.2±0.2; 6- p-nitrophenyl, 1.4±0.2 kcal mole− 1. Barriers to inversion of the N atom at position 2 are in the region 14.1–15.6 kcal mole− 1. The conformational behaviour of the tetrahydro-1, 2, 5- ...