Stereochemical studies of some <i>t</i>-3-methyl-r-2,<i>c</i>-6-diphenylpiperidin-4-one azine derivatives

Abstract

¹H and ¹³C NMR spectra are recorded for six <i>t-</i>3-methyl-r-2,<i>c</i>-6-diphenylpiperidin-4-one azine derivatives <b>8-13</b> in CDCl₃ and analysed. The proton spectra reveal the presence of two isomers in solution for the azines <b>12,13</b> and <b>8</b> and one isomer for <b>9-11</b>.In all azines the N-N single bond is found to be <i>anti </i>with respect to methyl group at C-3 in the piperidone ring and the two C=N bonds are <i>trans </i>with respect to N-N single bond (<i>s</i>-<i>trans</i> form). In the azines <b>9-11</b> the azomethine proton is found to be <i>syn </i>with respect to N-N bond. The other azines <b>12,13</b> and <b>8</b> exist as a pair of diastereoisomers in solution.