Duclaxin Ethyl Acetate Solvate,2C29H22O11.C4H8O2

Duclauxin, [8R-(8 alpha,8a beta,15a beta,15b alpha,16S*)]-16-(acetyloxy)-8a,15a-dihydro-4,11-dihydroxy-8a-methoxy-6,9-dimethyl-7H-8,15b-methano-1H,3H,12H-benzo-[de]cyclohepta[1,2-g:3,4,5-d'e']bis[2]benzopyran-3,7,12,15(8H)-tetrone, cocrystallized with ethyl acetate solvent (2:1). Duclauxin, an antitumor agent, when isolated from Penicillium herquei displays an unusually low melting point (469-471 K) compared with duclauxin from P. duclauxii or P. stipitatum (503 and 508-509 K, respectively), even though all spectral characterizations of duclauxin from these three sources indicate identical substances. The X-ray structural analysis of duclauxin from P. herquei reveals the presence of an ethyl acetate molecule, which is a likely explanation for the abnormal melting point. The duclauxin molecular structure consists of two largely planar halves which are held by the remaining atoms into an approximate open clam-shell configuration. Significant intramolecular hydrogen bonding is observed between the phenolic hydroxyl groups and lactonic carbonyl O atoms; the only significant intermolecular hydrogen bonding is between the ketonic O(3) atom of one duclauxin molecule to the phenolic O(6) atom in the other. There are no especially close intermolecular contacts between ethyl acetate and either of the duclauxin molecules