Process for the preparation of apovincaminic acid ester derivatives

Abstract

The invention concerns a new process for the preparation of apovincaminic acid ester derivatives of the general formula (I) ##STR1## wherein R.sup.1 and R.sup.2 independently represent an alkyl group having 1 to 6 carbon atoms, and pharmaceutically acceptable salts thereof. According to the invention the apovincaminic acid ester derivatives of the general formula (I) are prepared by reacting the corresponding 9- and/or 10- and/or 11-halo-14-oxo-15-hydroxyimino-E-homo-eburnane derivatives with an alkanol of the general formula R.sup.1 --OH, wherein R.sup.1 is as defined above, and with a dehydrating concentrated acid, and subsequently reducing the 9- and/or 10- and/or 11-halo-apovincaminic acid esters obtained, selectively on the aromatic ring. Alternatively, the 9- and/or 10- and/or 11-halo-apovincaminic acid esters can also be used as starting materials. The invention includes the preparation of racemic and optically active apovincaminic acid ester derivatives and of their pharmaceutically acceptable salts, as well.

Dependencies are inferred from the claim text.