process for preparation of apovincaminiques acid esters and pharmaceutical compositions thus obtained, esters prepared with these esters

摘要

A process is disclosed for the preparation of racemic cis or trans apovincaminic acid esters of the formula (I) IMAGE (I) and the corresponding optically active derivatives of the formulae (Ia) IMAGE (Ia) and/or (Ib) IMAGE (Ib) and/or (Ic) IMAGE (Ic) and/or (Id) IMAGE (Id) wherein R1 and R2 are identical or different alkyl groups having 1 to 6 carbon atoms. Apovincaminic acid alkyl esters are well-known vasodilating compounds.