New precursor of tetraterpenoids from the soft coral Sarcophyton glaucum.

One new precursor of tetraterpenoids, Sarglaucol (1), along with eight known compounds have been isolated from the soft coral Sarcophyton glaucum collected from the Sanya Bay, Hainan Island, China. Their structures were elucidated through spectroscopic techniques including 1D- and 2D-NMR, and their relative configurations were also assigned by NMR and NOESY analysis. Compounds 1 showed weak antitumour activities.

New norsesquiterpene and sesquiterpene from a soft coral of the genus Nephthea.

A new norsesquiterpene nephthediol (1) and a new sesquiterpene nephthetetraol (2) were isolated with guaianediol (3) from a soft coral of the genus Nephthea. Their structures were deduced on the basis of spectroscopic methods.

Two new sesquiterpenoids from the soft coral Sinularia polydactyla (Ehreberg).

Two new sesquiterpenoids, polydactins A (1) and B (2) and a known sesquiterpene, 10alpha-hydroxycadin-4-en-15-al (3), were isolated from the soft coral Sinularia polydactyla (Ehreberg). Their structures were determined mainly by spectroscopic methods. Polydactin A (1) showed moderate cytotoxic activities against human oral epidermoid carcinoma cell lines (KB) and human breast carcinoma (MCF) tumour cell lines (in vitro).

Two new bioactive sesquiterpenes from the soft coral Sinularia sp.

Two new sesquiterpenes, 1S*, 4R*, 5S*, 6R*, 7S*, 10S*-1(5), 6(7)-diepoxy-4-guaiol (1) and 1S*, 4S*, 5S*, 10R*-4,10-guaianediol (2) have been isolated from the ethyl acetate soluble portion of the soft coral Sinularia sp., and their stereostructure were determined by spectroscopic methods and by X-ray single crystal analysis. Both compounds showed antioxidant and cytotoxic activities.

Cytotoxic diterpenoids from the soft coral Sinularia microclavata.

The soft coral Sinularia microclavata collected from the bay of Sanya, Hainan Island, China, yielded a new diterpenoid, microclavatin (1), and a known cembranolide, capillolide (2). The structure of compound 1 was determined on the basis of spectroscopic methods and X-ray single-crystal diffraction analysis. Microclavatin (1) showed cytotoxic activities against tumor cell lines KB and MCF with IC50 values of 5.0 and 20.0 microg/mL, respectively, and capillolide (2) showed potent cytotoxic activity against tumor cell lines (A-549) with an IC50 value of 0.5 microg/mL.

New hemiketal steroid from the soft coral Cladiella sp.

[structure: see text] A new hemiketal steroid, named cladiellin A (1), was first isolated from the soft coral Cladiella sp. Its structure was determined by spectroscopic methods and X-ray analysis. Compound 1 easily converted to 1a when NMR spectra were measured in CDCl(3) solution and quickly changed to 1b when pyridine was used. The structures of dehydrated products 1a and 1b were determined by spectroscopic analysis. Bioassay showed that all these three compounds showed antioxidant activity.

New tetracyclic diterpenoid and new ceramides from the soft coral Sinularia conferta.

The new tetracyclic diterpenoid confertdiate (1) and two new ceramides, (2) and (3), have been isolated from the soft coral Sinularia conferta, collected from Sanya Bay, Hainan Island, China. Their structures have been elucidated by spectroscopic analysis, and comparison of the 13C NMR data with those of the known diterpenoid isomandapamate confirmed the structure of 1.

Two new cytotoxic tetracyclic tetraterpenoids from the soft coral Sarcophyton tortuosum.

Two new cytotoxic tetracyclic tetraterpenoids, methyl tortuoate A (1) and methyl tortuoate B (2), along with the known methyl sartortuoate (3) were isolated from the soft coral Sarcophyton tortuosum. The structures of 1 and 2 were established by spectroscopic methods, mainly on the basis of 2D NMR techniques, and were confirmed by single-crystal X-ray diffraction analysis. The cytotoxic activities of these compounds were carried out in vitro on human nasophyringeal carcinoma (CNE-2) and murine lymphocytic leukemia (P-388) tumor cell lines.

Synthesis of polyhydroxysterols (III): synthesis and structural elucidation of 24-methylenecholest-4-en-3beta,6 alpha-diol.

Using stigmasterol as the starting material, 24-methylenecholest-4-en-3beta,6 alpha-diol (2) was synthesized in eight steps in 13% overall yield. The introduction of the sterol side-chain was carried out using (3-methyl-2-oxobutyl)-triphenylarsonium bromide (11) and K(2)CO(3) in a solid-liquid phase-transfer Wittig reaction. Construction of the steroidal nucleus was finished by oxidation of 24-methylenecholest-5-en-3beta-ol (9) with pyridinium chlorochromate (PCC) in dichloromethane at ambient temperature and by reduction of 24-methylenecholest-4-en-3,6-dione (10) with NaBH(4) in the presence of CeCl(3).7H(2)O.