Synthesis of Menthol Glycinates and Their Potential as Cooling Agents

A convenient method of synthesis has been developed for a new class of potential cooling agents, menthol glycinates. These compounds are prepared in two synthetic steps, starting from bromoacetyl bromide and (−)-menthol. The resulting brominated menthol ester readily undergoes substitution reactions with NH₃ and 1° or 2° amines to provide menthol glycinates. For most of the prepared compounds, the two-step synthetic procedure requires no aqueous phase extractions.