The conformation of the NH-groups in piperazines, hexahydropyrimidines, tetrahydro-1,2- and 1,3-oxazine, and tetrahydro-1,3-thiazine

Abstract

I.r. band shapes and electric dipole moments show that the predominant conformers for tetrahydro-1,3-oxazine, tetrahydro-1,3-thiazine, and 1-t-butylhexahydropyrimidine are those with the NH axial; the predominant conformer for tetrahydro-1,2-oxazine is that with NH equatorial as determined by the same methods.