Absolute configuration and conformational analysis of (–)-(R)-deprenyl and its homologues

Abstract

The absolute configuration of (–)-N,α-dimethyl-N-prop-2-ynylphenethylamine was determined using the isomorphous HCl and HBr salts. Beside X-ray analysis, the conformation of the free base, of the salt, and of the C-alkyl derivatives was studied by ¹H and ¹³C n.m.r. techniques and potential-energy calculations. In the the solid state the extended conformer was observed, in solution the proportion of gauche-folded conformer increases with the bulkiness of R and decreases upon protonation of the nitrogen atom.