Talipexole is a dopamine agonist that is marketed as a treatment for Parkinson's disease in Japan by Boehringer Ingelheim; it was introduced in 1996. As of December 2014 it was not approved for marketing in the US nor in Europe.
Synthesis
The N-alkylation of azepan-4-one [105416-56-6] (1) with allyl bromide in the presence of potassium carbonate gives 1-allyl-azepan-4-one (2). This is halogenated with molecular bromine in acetic acid to give 1-allyl-5-bromohexahydro-4-azepinone (3). The last step involves cyclization with thiourea (4) in refluxing ethanol, completing the synthesis of talipexole (5). ==See also==