Duclauxin Ethyl Acetate Solvate, 2C29H22O11.C4H8O2

Abstract

Duclauxin, [8R-(8a,8afl,15afl,15ba,16S*)]-16-(acetyloxy)-8a, 15a-dihydro-4,1 l-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 0(3) atom of one duclauxin molecule to the phenolic 0(6) atom in the other. There are no especially close intermolecular contacts between ethyl acetate and either of the duclauxin molecules.

New Duclauxamide from Penicillium manginii YIM PH30375 and Structure Revision of the Duclauxin Family

“…In contrast, a simulation with the C-9′ S configuration generated a dihedral angle of ∼90° for H-8′/H-9′, which should produce the smaller 3 J H,H value that was consistent with the broad singlet peaks (H-8′ and H-9′) we observed experimentally (Figure B). Thus, the relative configuration of C-8′/C-9′ is opposite to the previously proposed C-9′ R stereochemistry . Surprisingly, in the pertinent references, br.s peaks of H-8′ were presented for all the structurally related duclauxin analogues .…”