Mechanistic Studies of Octahydrophenazine Formation from a 2-Hydroxycyclohexanone/Ammonium Acetate Model System in Ethanol

Abstract

Synopsis Model systems composed of 2-hydroxycyclohexanone and ammonium acetate in a mole ratio of 1 to 3 were set up to study the formation of octahydrophenazine (OHP). Octahydrophenazine and an intermediate were isolated and characterized by GC/MS (EI and CI). This intermediate was the condensation pfoduct between a molecule of 2-hydroxycyclohexanone and 2-amino-cyclohexanone via the Schiff base formation mechanism. A larger amount of the intermediate than of OHP was found in the solvent system containing less than 20% ethanol, the relative proportion of the intermediate decreasing as the percentage of ethanol was increased. The formation mechanism for OHP is proposed.