A new pentacyclic cucurbitane glucoside, named aoibaclyin (1) and a new triterpene (2) have been isolated from the EtOH extract of the fruits of Gymnopetalum integrifolium Kurz (Cucurbitaceae), together with three known compounds, bryoamaride (3), 25-O-acetylbryoamaride (4) and beta-sitosterol 3-O-beta-D-glucopyranoside (5). The structures of these compounds were elucidated by spectroscopic ana...

A new pentacyclic stemona alkaloid, stemocurtisine (2), with a novel pyrido[1,2-a]azapine A,B-ring system, has been isolated from a root extract of Stemona curtisii. The structure and relative stereochemistry was determined by spectral data interpretation and X-ray crystallography.

A racemic, prenylated polyketide dimer, oxazinin A (1), was isolated from a novel filamentous fungus in the class Eurotiomycetes, and its structure was elucidated spectroscopically. The pentacyclic structure of oxazinin A (1) is a unique combination of benzoxazine, isoquinoline, and a pyran ring. Oxazinin A (1) exhibited antimycobacterial activity and modestly antagonized transient receptor pot...

A novel alkaloid with an unprecedented fused-pentacyclic skeleton and six-consecutive asymmetric centers, cephalocyclidin A (1), has been isolated from the fruits of Cephalotaxus harringtonia var. nana, and the structure was elucidated on the basis of spectroscopic data. The relative and absolute stereochemistry of 1 was determined by a combination of NOESY correlations, X-ray crystallographic ...

The structure of a new antitumor antibiotic, myrocin C, from a strain of Myrothecium verrucaria was characterized as a pentacyclic pimarane diterpene composed of a gamma-lactol group and a unique cyclopropane ring on the basis of its physico-chemical properties and spectroscopic data as well as a single-crystal X-ray diffraction analysis of its monoacetyl derivative.

recently, e. m'{a}v{c}ajov'{a} and m. v{s}koviera proved that every bidirected eulerian graph which admits a nowhere zero flow, admits a nowhere zero $4$-flow. this result shows the validity of bouchet's nowhere zero conjecture for eulerian bidirected graphs. in this paper we prove the same theorem in a different terminology and with a short and simple proof. more precisely, we p...

[formula: see text] A novel pentacyclic polyhydroxylated sterol, xestobergsterol A (1a), has been synthesized in 24 steps and in good overall yield from stigmasterol 17. The key steps of the synthesis are the Breslow remote functionalization of the polyoxygenated steroid derived from 25 and the base-catalyzed epimerization-aldol condensation of the dione derived from 27.

Five new monoterpene indole alkaloids, naucleamides A-E (1-5), were isolated from the bark and wood of Nauclea latifolia, and the structures and relative stereochemistry were elucidated from the spectroscopic data. Naucleamide E (5) is a unique monoterpene indole alkaloid possessing a pentacyclic ring system with an amino acetal bridge.

A new farnane-type pentacyclic triterpene, farnan-2-one-3 beta-ol (mimusopfarnanol), was isolated from the stem bark of Mimusops elengi L. along with the known triterpenoids, farnan-3-one, olean-18-en-2-one-3-ol and lup-20 (29)-en-3 beta-ol and their structures have been characterized on the basis of spectral data analyses and chemical reactions.

The first enantioselective total synthesis of (+)-stachyflin, a potential anti-influenza A virus agent, was achieved; the method features a BF(3).Et(2)O-induced domino epoxide-opening/rearrangement/cyclization reaction to stereoselectively form the requisite pentacyclic ring system in one step.