COMPLEX OF A LISURIDE DERIVATIVE AND (S)-NAPROXEN

The structure of a complex between (+)-1-allyllisuride and the (+)-(S) isomer of 2-(6-methoxy-2-naphthyl)-propionic acid (naproxen), (+)-(5R ,8S)-1-allyl-9,10-didehydro-8-(N', N'-diethylureido)-6-methylergolin-6 -ium 2-(6-methoxy-2-naphthyl)propionate 2-(6-methoxy-2-naphthyl)propio nic acid acetonitrile solvate hydrate, C23H31N4O+.C14H13O3-.C14H14O3.C 3H8O.H2O, has been determined. At the pH of the crystallization condit ions, each molecule of allyllisuride is protonated and interacts with two molecules of naproxen in different modes; with one molecule, a pi- pi interaction seems to occur between aromatic moieties, while with th e other, which appears to be deprotonated, hydrogen bonds are present. The electrostatic interactions seem sensitive to the configuration at the asymmetric C atom of naproxen and are likely to be responsible fo r the enantio-discriminative process, In the asymmetric unit, one mole cule of isoprapyl alcohol and one molecule of water are present. They are connected through a network of hydrogen bonds to the carbonyl grou p of allyllisuride and to the carboxyl groups of the two molecules of naproxen.