The optically active 3,16-trans-eburnamenine ester (I), a by-product in the manufacture of vinpocetine, is hydrogenated to yield the 14,15-dihydro derivative (II) having a beta-oriented carbomethoxy group. Reduction with LiAlH4 gives, with concomitant inversion of configuration at C-14, the alcohol (III), RGH-0537.