The 13C NMR spectra of many derivatives of benzoic acid, which are of great interest in connection with their reactivity and biological activity, have already been examined thoro~ ghly.'~ However, no work has been published on the 13C NMR spectra of potentially analgesic di-and tri-substituted derivatives of esters, thioesters or amides of benzoic acid with a (dialkoxycarbonyl)(alkoxy, thioalkyl, cyano or alkylamino) methylamino substituent ...
