Synthesis and absolute configuration of the four possible stereoisomers of prandiol

Isobenzofuranones from the aerial parts of Leontopodium leontopodioides (Wild.) Beauv

A phytochemical investigation to obtain new triglyceride (TG) accumulation inhibitors resulted in the isolation of six new isobenzofuranones, leontopodiols A (1), B (2), leontopodiosides C (3), D (4), E (5), F (6), together with three known ones (7-9) from the aerial parts of Leontopodium leontopodioides (Willd.) Beauv. The structures of these isolates were identified by routine NMR experiments, optical rotation determination, electronic circular dichroism (ECD) calculation, along with chemical reaction. Moreover, compounds 1, 2, 5, and 7-9 displayed TG accumulation inhibitory effects on HepG2 cells.

Antiviral and anti-inflammatory metabolites from the soft coral Sinularia capillosa

Chemical investigations of the soft coral Sinularia capillosa resulted in the isolation of one new tetraprenylbenzoquinone, capilloquinone (1), two new furanobenzosesquiterpenoids, capillobenzopyranol (2) and capillobenzofuranol (3), one new furanosesquiterpenoid, capillofuranocarboxylate (4), and five previously characterized metabolites, comprising (E)-5-(2,6-dimethylocta-5,7-dienyl)furan-3-carboxylic acid (5), 2-[(2E,6E)-3,7-dimethyl-8-(4-methylfuran-2-yl)octa-2,6-dienyl]-5-methylcyclohexa-2,5-diene-1,4-dione (6), 2-[(2E,6E)-3,7-dimethyl-8-(4-methylfuran-2-yl)octa-2,6-dienyl]-5-methylbenzene-1,4-diol (7), (-)-loliolide (8), and 3,4,11-trimethyl-7-methylenebicyclo[6.3.0]undec-2-en-11alpha-ol (9). The structures of 1-4 were elucidated through extensive spectroscopic analysis. The cytotoxicity, anti-HCMV (human cytomegalovirus) activity, antibacterial activity, and anti-inflammatory effects of 1-9 were evaluated in vitro.

Cyclodextrin-based liquid chromatographic enantiomeric separation of chiral dihydrofurocoumarins, an emerging class of medicinal compounds

A set of 28 racemic dihydrofurocoumarins in which the stereogenic center is located in the furan ring have been synthesized. Currently no effective asymmetric synthesis of this class of compounds exists, although their enantiomers are produced biologically by certain plants. Their diverse medicinal properties are being investigated in several laboratories. The enantioselective separation of these dihydrofurocoumarins by three native and six derivatized cyclodextrins has been evaluated in the reversed-phase mode, the polar organic mode, and normal-phase mode. The hydroxypropyl-beta-cyclodextrin is the most effective chiral stationary phase (CSP) at separating the dihydrofurocoumarins into enantiomers, showing some enantioselectivity for 22 dihydrofurocoumarins, and baseline resolving 16 of the 28 compounds in the reversed-phase mode. The acetyl-beta-cyclodextrin and 2,3-dimethyl-beta-cyclodextrin also showed enantioselectivity for a large number (18 and 17, respectively) of dihydrofurocoumarins in the reversed-phase mode. The native cyclodextrins are ineffective and the aromatic derivatized beta-cyclodextrins are only marginally effective at separating the furocoumarin enantiomers in the reversed-phase mode. The polar organic mode and the normal-phase mode have also been evaluated with these CSPs, but no enantioseparations were observed.

An efficient approach to dihydrofurocoumarins via palladium-catalyzed annulation of 1,3-dienes by o-iodoacetoxycoumarins

The palladium-catalyzed annulation of 1,3-dienes by o-iodoacetoxycoumarins provides an efficient method for the synthesis of biologically interesting dihydrofurocoumarins. The presence of the acetyl group on the phenolic oxygen and the use of silver carbonate as a base are crucial for this process. This reaction is very general and regio- and stereoselective, and a wide variety of terminal, cyclic, and internal 1,3-dienes can be utilized. Derivatization of the annulation products provides an efficient approach to numerous analogues of natural products.