From the ethyl acetate soluble fraction of twigs of Magnolia denudata (Magnoliaceae), seven new neolignan derivatives, 1-7, were isolated along with eighteen known lignan and neolignan derivatives, 8-25. The structures of the new neolignans were elucidated by means of spectral methods, especially by 1H-NMR and 13C-NMR spectra, and two dimensional NMR methods such as 1H-detected heteronuculear m...

Building on the ideas of a previous paper [part 1, J. Phys. Chem. A 1999, 103, 2883] we present a new molecular similarity method based on the topology of the electron density. This method is directly applicable to QSARs and is called quantum topological molecular similarity (QTMS). It has been tested for five sets of carboxylic systems including para- and meta-benzoic acid, para-phenylacetic a...

In the crystal structure of the title compound, C(43)H(46)NO(13)·0.5H(2)O, the mol-ecule assumes a U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The mol-ecule contains eight alicyclic and heterocyclic rings. The cyclo-hexane rings adopt chair conformations, the other three six-membered carbocyclic rings form a bicyclo-[2...

Paclitaxel is one of the most important anti-cancer agents introduced during the last 20 years. However, the use of paclitaxel is limited by undesirable side effects as well as the development of drug resistance. Here, we report a synthetic strategy towards spiro-bicyclo[2.2.2]octane derivatives, which includes double Michael addition and ring-closing metathesis as key synthetic steps. This str...

Penicitroamide (1), a new metabolite with a new framework, was isolated from the ethyl acetate extract of the PDB (Potato Dextrose Broth) medium of Penicillium sp. (NO. 24). The endophytic fungus Penicillium sp. (NO. 24) was obtained from the healthy leaves of Tapiscia sinensis Oliv. The structure of penicitroamide (1) features a bicyclo[3.2.1]octane core unit with a high degree of carbonylizat...

In the title coordination polymer, [Hg(2)Cl(4)(C(6)H(12)N(2))](n), each Hg(II) center within the chain is four-coordinated by one terminal Cl atom, two bridging μ(2)-Cl atoms, and one N-atom donor from a μ(2)-1,4-diaza-bicyclo-[2.2.2]octane (μ(2)-daco) ligand in a distorted tetra-hedral geometry. The daco ligand acts as an end-to-end bridging ligand and bridges adjacent Hg(II) centers, forming ...

Alkynyl allenes undergo intramolecular Pauson-Khand (P-K) cycloadditions to provide functionalized α-methylene and 4-alkylidene cyclopentenones in good yields. These studies have demonstrated a dependence of the π-bond selectivity of this cycloaddition on the substitution pattern of the allene. The Pauson-Khand (P-K) reaction is a multi-component reaction that has been exploited extensively in ...

New and simple protocols are described for the conversion of the enzymatically-derived and enantiomerically pure cis-1,2-dihydrocatechol (X = I) and its 6-methylated derivative into either antipodal form of compounds embodying the tricyclic frameworks of terpenoids . Key steps include intramolecular Diels-Alder (IMDA) and (in some cases) singlet or triplet-based photochemical processes.