Resolution and absolute configuration of an ergoline-related dopamine agonist, trans-4,4a,5,6,7,8,8a,9-octahydro-5-propyl-1H(or 2H)-pyrazolo[3,4-g]quinoline
The title compound (+/-)-5 (R = Pro) (LY141865) has been resolved into a (-) isomer and a (+) isomer as the D- and L-tartrate salts, respectively. Biological studies have shown that dopamine agonist activity is a property of only the (-) isomer. Crystallographic analysis has proven that the absolute configuration of the active (-) isomer is the same as that of the natural ergolines.