Two new tetracyclic triterpenoid trilocularol A and trilocularol A 3-glucoside and one pentacyclic triterpenoid tirlocularoside A were isolated from Corchorus trilocularis L., their structure were elucidated as 3beta,6alpha,16alpha,20(S),27-pentahydroxydammar-24(Z)-ene (1), 3beta-D-glucopyranosyloxy-6alpha,16alpha,20(S),27-tetrahydroxydammar-24(Z)-ene (2) and 2alpha,3beta,19alpha,30-tetrahydrox...

the center (periphery) of a graph is the set of vertices with minimum (maximum)eccentricity. in this paper, the structure of centers and peripheries of some classes ofcomposite graphs are determined. the relations between eccentricity, radius and diameterof such composite graphs are also investigated. as an application we determinethe center and periphery of some chemical graphs such as nanotor...

we study the set of all determinants of adjacency matrices of graphs with a given number of vertices. using brendan mckay's data base of small graphs, determinants of graphs with at most $9$ vertices are computed so that the number of non-isomorphic graphs with given vertices whose determinants are all equal to a number is exhibited in a table. using an idea of m. newman, it is proved that if $...

An efficient synthesis of the N-methylwelwistatin tetracyclic core in only two steps from Kornfeld's ketone is described, whose key transformation involves the generation of a fused bicyclo[4.3.1]decane ring system through a one-pot sequence comprising a Michael-intramolecular aldolization anionic domino process and a DBU-promoted hydrolysis of the N-pivaloyl protecting group. Besides providing...

An efficient synthesis of the tetracyclic steroid core, 19, of rhodexin A and sarmentogenin is reported. An initial inverse-electron-demand Diels-Alder reaction of the acyldiene 6 with the silyl enol ether 7a gave the cycloadduct 8 with the required four contiguous stereocenters in a single step. This compound was then transformed into the methylated enedione 13 which afforded after a reductive...

DESCRIPTION Celexa (citalopram HBr) is an orally administered selective serotonin reuptake inhibitor (SSRI) TM with a chemical structure unrelated to that of other SSRI’s or of tricyclic, tetracyclic, or other available antidepressant agents. Citalopram HBr is a racemic bicyclic phthalane derivative designated (±)-1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitr...

The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl)-N-methylethanamine (2) as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl)-N-methylmethaneamine (1) was described. The key intermediate 9-(prop-2-en-1-yl)-9,10-dihydro-9,10-propanoanthracen-12-one (7) was successfully synthesized via a [4+2] cycloaddition of alpha-bromoacrolein and...

This review illustrates the various studies made to investigate the activity of N-pyrrylarylsulfone containing compounds as potential antiviral, anticancer and SNC drugs. A number of synthetic approaches to obtain tetracyclic, tricyclic and non-cyclic compounds, and their biological activity with regard to structure-activity relationships (SARs) have been reviewed. The literature reviewed here ...

In the title compound, C(30)H(41)NO(6), the three six-membered rings adopt chair conformations and the stereochemistry of the A/B and B/C ring junctions are trans. The five-membered ring D adopts an envelope conformation, with the methyl-ene C atom as the flap. The title compound was synthesized via esterification, Tollens reaction, 1,5-hydride shift from the natural tetracyclic diterpenoid iso...

Marine myxobacteria (Enhygromyxa, Plesiocystis, Pseudoenhygromyxa, Haliangium) are phylogenetically distant from their terrestrial counterparts. Salimabromide is the first natural product from the Plesiocystis/Enhygromyxa clade of obligatory marine myxobacteria. Salimabromide has a new tetracyclic carbon skeleton, comprising a brominated benzene ring, a furano lactone residue, and a cyclohexane...