J. C. Braekman

Chemical Studies of Marine-invertebrates .43. Novel Sesquiterpenes From Clavularia-inflata and Clavularia-koellikeri (coelenterata, Octocorallia, Stolonifera)

Abstract Two novel sesquiterpenes, 12-acetoxycyclosinularane ( 1 ) and 12-acetoxysinularene( 2 ),have been isolated from Clavularia inftata . Their structures have been determined by X-ray diffraction analysis and chemical correlation respectively. Moreover, the new aromadendrane sesquiterpene(1R * , 1aS * , 4R * , 7R * , 7aS * , 7bS * , 5Z)-4,4a,7-trihydroxyaromadendr-5-en-8-oic acid methyl ester ( 19 ) has been isolated from the related species C. koellikeri . Its structure has been established by X-ray diffraction analysis. These compounds are the first sesquiterpenes isolated from Octocorallia of the order Stolonifera.

A Novel Type of Bis-quinolizidine Alkaloid From the Sponge Petrosia-seriata

Abstract The structure of petrosin, the major alkaloid isolated from the sponge Petrosia seriata , has been determined by X-ray diffraction analysis. Petrosin is the first member of a new class of bis-quinolizidine alkaloids containing a C-16 macrocycle.

Secotrinervitane, a Novel Bicyclic Diterpene Skeleton From a Termite Soldier

Abstract The structure of 3α-acetoxy-15β-hydroxy-7,16-secotrinervita-7,11-diene, a diterpene possessing a novel bicyclic cembrane-derived carbon skeleton, has been determined by X-ray diffraction analysis.

Chemical Studies of Marine-invertebrates .38. Delta-9(15)-africanene, a New Sesquiterpene Hydrocarbon From Sinularia-polydactyla (coelenterata, Octocorallia, Alcyonaceae)

The isolation and structure determination ofΔ 9(15)-africanene (1) from the soft coralSinularia polydactyla is described.

Chemical studies of marine invertebrates. XLI. Sigmosceptrellin-A methyl ester a nor-sesterterpenoid peroxide from the sponge sigmosceptrella laevis.

Abstract Structure 1 has been established for sigmosceptrellin-A methyl ester, a novel ichtyotoxic nor-sesterterpenoid from the sponge S. laevis.

Chemical composition of the frontal gland secretion from soldiers of nasutitermes lujae (termitidae, nasutitermitinae)

Abstract The front gland secretion of soldiers of the West African Nasute termite Nasutitermes lujae contains the monoterpene terpinolene 1, and five diterpenes, four of them (5 to 8) belonging to the trinervitane skeleton while the fifth (3) is a secotrinervitane derivative. 3 and 8 are new derivatives whose structure has been established by chemical correlation and by X-ray diffraction analysis respectively.

Chemical communication in the marine environment

ABSTRACT This review is devoted to chemical communications between marine organisms. Interspecies as well as intraspecies chemical communication systems are surveyed and discussed. A special attention has been drawn to systems for which the structure of the chemical vector(s) is Known.

A new 20,24-dimethylscalarane derivative isolated from the sponge Carteriospongia foliascens, C30H42O6

Methyl 12a-acetoxy-20,24-dimethyl-16,24dioxoscalara-14,17-dien-25-oate, M r = 498.66, orthorhombic, P212121, a 7.943 (2), b = 14.198 (5), c = 2 5 . 2 3 2 ( 6 ) A, V = 2 8 4 5 ( 1 ) A 3, Z = 4 , D x= 1.16 g cm -3, Mo Ka, 2 = 0.71069 ]k, ~t = 0.85 cm -I, F(000)= 1080, T = 2 9 1 K, R =0 .053 for 1676 observed reflections. Particular features of this molecule are the high degree of unsaturation of ring D [it contains two double bonds of 1.327 (8) and 1.339 (8) A] and the presence of an axial ethyl group at the C(4) position. Introduction. In the course of our work on the chemical defense of sponges, six new 20,24-dimethylscalarane derivatives have been isolated from the ichthyotoxic fraction of the chloroform extract of the marine sponge Carteriospongia foliascens (Spongiidae-Dictyoceratida) collected around Laing Island (King Leopold III Biological Station, Laing Island, Papua-New Guinea; contribution No. 78). We describe here the determination of the molecular structure of one of these (1) (Fig. 1), isolated as its methyl ester (2). * Senior Research Associate of the National Fund for Scientific Research (Belgium). 0108-2701/85/081222-03501.50 Experimental. D m not measured. Parallelepiped crystal 0.22 x 0.25 × 0.45 mm. Lattice parameters refined using 15 reflections in the range 3 ° < 28 < 17 °. Syntex P21 diffractometer, graphite-monochromatized Mo K~t radiation. 2418 independent hkl reflections with sin8/2 < 0.561 A -l, 1676 with I > 2.5a(/). Standard reflection 201 checked every 50 reflections: no significant variation. No correction for absorption or extinction. Structure solved by MULTAN80 (Main, Fiske, Hull, 28 CH3COO 25 33 , 23 C O O R 0