Process for the preparation of rotigotine

Abstract

A process for the preparation of Rotigotine (1) and of pharmaceutically acceptable salts thereof, which comprises the reductive amination of an amine of formula 6 with the 2-thienylacetic acid-sodium boron hydride complex and which makes use of hydrobromide 5 as an intermediate The process is advantageous from the industrial point of view in that it allows to obtain Rotigotine with high enantiomeric purity starting from optically active 5,6,7,8-tetrahydro-6-(S)—N-propylamino-1-methoxy-naphthalene (2), avoiding the use of dangerous reactives, the need for difficult chromatographic separation or the formation of by-products. Furthermore, two novel crystalline forms are disclosed.

1 . 2-N-Propyl-5-hydroxy tetraline hydrobromide 5