Preparation of Racemic cis- and trans-2-(2-Alkoxyphenylcarbamoyloxy)cycloheptylmethylpiperidinium Chlorides

Abstract

The synthesis of two pairs of the title diastereomers, which represent conformationally constrained analogues of the phenylcarbamate local anesthetics, is described. The synthesis was accomplished by starting from cycloheptanone and 2-alkoxyanilines and the intermediate diastereomers of 2-aminomethylcycloalkanols (VI, VII) were separated as their 4-nitrobenzoyl derivatives (IV, V) by extraction and fractional crystallization. The prepared compounds (VIIIa, VIIIb, IXa, and IXb) are assumed to be of help in interpreting the structure activity relationships within this class of drugs.