Process for the preparation of endo-nortropine using 8-benzyl-nortropan-3-one perchlorate as the intermediate, as well as the latter salt

Abstract

The invention relates to a process for the preparation of endo-nortropine using 8-benzyl-nortropan-3-one perchlorate, as well as the latter product. Endo-nortropine is the key product for the production of important azonia-spironortropanol esters, which are used as pharmaceuticals, particularly spasmolytics. There are three different synthesis methods for the preparation of said intermediate, which lead to different disadvantages. These problems are obviated by the present invention through the two-stage treatment of 8-benzyl-nortropan-3-one perchlorate with catalytically activated hydrogen, the starting product initially being prehydrogenated in aqueous suspension and at atmospheric pressure and ambient pressure with a palladium catalyst, at the end of the reaction the catalyst is recovered by filtration, the filtrate is passed over an anion exchanger and the now alkaline reacting solution is rendered turbulent at 1000 to 1500 r.p.m. with hydrogen activated by Raney nickel at atmospheric pressure and ambient temperature. This new synthesis method using the novel perchlorate salt as an intermediate is extremely economic and environmentally friendly and supplies substantially completely stereoselectively the desired endo-form of nortropine.

Dependencies are inferred from the claim text.