Richter Gedeon Vegyeszeti Gyar Rt

Laszlo Cibula

Csaba Szantay

Lajos Szabo

Gyorgy Kalaus

Janos Kreidl

Andras Nemes

Maria Farkas Nee Kirjak

Janos Sapi

The invention relates to a new enantioselective synthesis for the preparation of optically active 14-oxo-E-homo-eburnane derivatives of the formula (Ia) ##STR1## wherein R.sup.1 is alkyl having from 1 to 4 carbon atom. In the synthesis optically active 6-alkoxycarbonylhexahydroindoloquinolizinium salts are employed as starting materials, which contain a center of chirality at the site of attachment of the carboxyl group. This center of chirality preserves the optical activity of the optically active tryptophan ester from which this compound has been prepared until a new center of chirality is formed in the molecule in a configuration corresponding to the desired end product. The carboxyl group, which is not needed in the end product and only serves to preserving the optical activity can then be eliminated. Compounds of the formula (Ia) are known in the art and may be used in the synthesis of (+)-vincamine and (+)-apovincaminic acid ethylester.

Process for an enantioselective synthesis of optically active

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Budapest, Hungary

Laszlo Cibula