LAGON

The fatty acid composition of phospholipids from the New Caledonian sponge Cinachyrella aff.schulzei Keller was studied. More than 60 fatty acids were identified as methyl esters and N-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. Two isoprenoid fatty acids also were shown to be present, namely 4,8,12-trimethyltridecanoic and 5,9,13-trimethyltetradecanoic acids. The unusual 6-tetradecenoic, 6-pentadecenoic, 12-nonadecenoic and 26-methylheptacosanoic (iso-28:0) acids were found for the first time in sponge phospholipids. A series of six n-7 monoenoic long-chain fatty acids (C-23 to C-28) were identified, including the rare 16-tricosenoic, 18-pentacosenoic and 21-octacosenoic acids. Fifteen fatty acids possessing the typical 5,9 dienoic moiety accounted for 30% of the total fatty acid mixture. Two new fatty acids were identified, namely 5(Z)-octacosenoic and 27-methyl-5(Z),9(Z)-octacosadienoic (iso-5,9-29:2). Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the (Z) configuration.

MONTROUZIER

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Biologically active sesterterpenes of the manoalide family, thorectolide monoacetate (1) co-occurring with thorectolide (2), were isolated from a marine sponge Hyrtios sp. collected in New Caledonia.

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Lutoside, an unusual acyl-l-(acyl-6'-mannobiosyl)-3-glycerol 1 was isolated from the sponge-associated bacterial strain Microccocus luteus. Sructure elucidation was performed by sprectroscopic analysis and chemical transformations.

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Chemical investigation of the cytotoxic CH2Cl2-soluble extract of the marine tunicate Pseudodistoma arborescens led to the isolation of four brominated indole alkaloids, arborescidines A [1], B [2], C (3), and D [4], which were characterized by their spectral data, especially 2D nmr. Only arborescidine D [4] showed moderate activity (IC50 3 mug/ml) in vitro against the growth of KB human buccal carbinoma cells.

SMIB 6

It is shown that the demosponge Corallistes sp. (Tetractinomorpha, Lithistida, Corallistidae) collected in the Coral Sea, contains corallistin A (1), the second example, of a free porphyrin from a living organism. The compound proved to be active against the Kb cell line. In contrast with the geoporphyrins which do not bear any O-atom corallistin A (1) carries two carboxylic groups.

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Reported here are the novel free porphyrins corallistin B, C, D, and E, isolated as methyl esters 2a, 3a, da, and 5a, respectively, from the sponge Corallistes sp. (Lithistida) collected at the basis of the south New Caledonian coral reef. A protocol is also established for formylation of their Ni" complexes, which show a different reactivity pattern toward DMF/POCI, from metal complexes of deuteroporphyrins. Together with corallistin A, previously isolated as the methyl ester la, and the known deuteroporphyrin IX (isolated as 6a) also present in the sponge, the new corallistins, which may be thought to derive from protoporphyrin viu heme, account for an amazing 60% of the EtOH extract from the sponge.

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Agelastatin A, isolated from the axinellid sponge Agelas dendromorpha of the Coral Sea, is a new-skeleton alkaloid with, unusually for the oroidin family to which it belongs, marked cytotoxicity toward tumour cells in culture.

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Agelastatin A (l),a n unusual alkaloid ofthe axinellid sponge Agelas dendromorpha from the Coral Sea, can be selectively acetylated (+ 7) or methylated at OH-C(8a) (-+ 4), peracetylated (+ 8) or permethylated at OH-C(8a), NH(5), and NH(6) (+5), or, finally, subjected to C(9)-C(8a) (+ 14) or C(Sb)-C(Sa)B-elirnination (+11-13), in a regiospecific manner or not, depending on the reaction conditions. Under acidic conditions, compound 12 adds H,O or MeOH, regioselectively though not endolexo stereoselectively, giving transoidlcisoid mixtures 1/18 or 4/19, respectively. Similarly 11 or 13 add MeOH to give mixtures (-)-2/20 or 15/16, respectively. Compound 13 also adds AcOH giving mixture 8/17. The intermediate cisoid form obtained on treatment of 21 with H30+ undergoes N(5)-N(6) bridging affording pentacyclic 22 which constitutes a proof for the cisoid configuration. From conformational studies, rules are devised that allow assigning the configuration of these compounds from NMR data. In vitro comparative cytotoxicity assays of these compounds show that for high cytotoxic activity, such as of 1 in vivo, unsubstituted OH-C(8a), H-N(S), H-N(6) moieties are needed in the natural B/D transoid configuration.

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Natural free carboxylic acids from the hadromerid sponge Diacornus levii (Kelly-Borges and Vacelet) were esterified to yield the new cyclic norditerpene peroxides ent-muqubilin benzyl ester (= (aR,3S.6R)-a,6-dimethyl- 6-[(E )-4-methyl-6-(2,6,6-trimethyl-cyclohex-l-en-l-yl)hex-3-enyl]-l,2-dioxan-3-acaectiidc benzyl ester; 6), diacarnoate B methyl ester (= (aS,3S,6R)-a,6-dimethyl-6-{2-[(4aS,8aS)-3.4,4a,5,6,7,8,8a-octahydro-3-oxo- 2,5,5,8a-tetramethylnaphthalen-l-yl)ethyl}-l,2-dioxan-3-acetica cid methyl ester; 9). and deoxydiacarnoate B benzyl ester (= (ccS,3R,6R)-cc,6-dimethyl-6-{2-[(4aS,8aS)-3,4,4a,5,6,7,8,8a-octahydro-2,5,5,8a-tetramethyl-lnaphthalenyl]ethyl]-1,2-dioxan-3-acetiacc id benzyl ester; lo), which were isolated following extensive chromatography. The relative configuration of the peroxideicc-methylacetate moiety of 6, 9, and 10 was directly determined from their NMR spectra. The absolute configurations of the peroxide/cc-methylacetate moiety was deduced from comparative 'H-NMR data of the (S)- and (R)-phenylglycine methyl ester derivatives 7 and 8 as well as 11/13 and 12/14, all obtained from a mixture of the precursors of 3,6, and 10. The absolute configuration at the carbobicyclic moiety of enone 9 and of 10, is identical, as established by chemical interconversion, 9 and 10 belong to the normal labdane series according to empirical CD rules, applied either directly to 9 or to the parent (+)-sclareolide-derived enone 20. In contrast, molar rotation additivity rules suggest the enr-labdane configuration for 9 and 10. The epidioxides 1-3, 6, and 10 proved active in vim against the malaria parasite PIasmodiumfalciparum; especially the previously isolated methyl 3-epinuapapuanoate (2) was active against a chloroquine-resistant strain, and this with a good security index.

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Two 3 beta-methoxy secosteriods, named jereisterol A and B were isolated from the pacific sponge Jereicopsis graphidiophora Levi & Levi. Their structures, which combine rare 3 beta-methoxy and seco features, were determined as (24 R) 24-methyl-3-beta-methoxy-8-alpha,9-alpha-oxido-8,9-secocholesta-7,9(11)-diene (1) and (24R) 24-methyl-3-beta-methoxy-8,14-secocholesta-8,14-dione (2).

MUSORSTOM 4, SMIB 1, SMIB 2, SMIB 3, SMIB 4, SMIB 5, SMIB 6, VAUBAN 1978-1979

During our ongoing program of searching for new bioactive molecules from new-caledonian marine invertebrates, the opportunities occured recently to examine a "living fossil" crinoid Gymnocrinus richeri, discovered by B. Richer de Forges at 520m depth. In vivo this crinoid is saffron yellow with the stalk darker and tentacles dark yellow-green inside. A few minutes after collecting, outside the water, it turns readily dark-green. The green pigments, extractable with methanol, turned violet on very mild acidification. In this communication the structure of five violet pigments, which constitute a novel group of brominated phenanthroperylenequinones, will be discussed. These pigments have interesting stereochemical features, i.e. the axial chirality generated by the phenanthroperylenequinone system forced into a non planar helical shape. The assignment of the stereochemistry based on CD, NMR data and correlation with natural occuring perylenequinones will he presented. There is also considered the possible relationship between the violet pigments and the native yellow and green ones. A second "living fossil" organism from New Caledonia which we had the opportunity to examine is the starfish species Tremaster novae caledoniae collected at 530m depth off Nouméa. This organism contains a group of unusual steroids in which one hydroxyl group is sulphated, one is acetylated and a third one is esterified with glucose-I-phosphate. The results of the chemical investigation of the sponge Jereicopsis graphidiophora (new genus) and Erylus sp. collected at ca. 500m depth off Nouméa, will he also presented. While the 3B- hydroxy steroids were totally absent, the extracts of J. graphidiophora contain unique 38- hydroxy steroids. L'wo of them combine the unique 38- methoxyl group with a rare secostructure. The polar extracts of Erylus sp. contain two terpenoid oligoglycosides. Sequential analysis of the oligosaccharide portions was achieved by modern 2D-NMR techniques.

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The isolation acd characterization of two novel triterpene glycosides from a sponge of the genus Eryhs, collected at a depth of 500 m in the South of New Caledonia, are described. The structures are characterized by the presence of a branched oligosaccharide chain, composeí1 of three (1) and four (2) D-galactopyranose units, respectively. Analysis of the oligosaccaride structures was achieved by { 'H, 'H} correlation spectroscopy, two-dimensional homonuclear Hartmann-Hahn, and 'H-detected ('H, I3C} one bond (HMQC) and multiple-bond (HMI3C) shift correlation NMR experiments. The novel lanostane derived aglycone features a mre 14-carboxyl grdup and a 24-methylene, 25-methyl side chain.

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Three new macrolides 2-4 have been isolated with sphinxolide 1 from the manne sponge N. superstes collected off New Caledonia . The structures of the new compounds were determined by interpretation of NMR spectral data as well as by comparison of spectral data with those of 1. These compounds were highly cytotoxic against various human carcinoma cells.

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BIOCAL

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A novel cyclodepsipeptide, neosiphoniamolide A [1], has been isolated from the sponge Neosiphonia superstes. The structure of 1, which contains a 12-carbon hydroxy acid, glycine, valine, and a halogenated tyrosine residue in an 18-membered ring, is related to jaspamide and the geodiamolides, previously isolated from sponges. The structure was solved by spectroscopic analysis.

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Five new amino acid derivatives were isolated from the New Caledonian sponge Jaspis carteri, together with known bengamides A and B. The structures of the new compounds were determined by interpretation of their spectral data and by comparison with spectral data of known bengamides. Compounds 4-7 are simply the tridecanoate and pentadecanoate analogues of the original bengamides A and B, whereas compound 8 is a caprolactam formamide derivative of bengamide B.

BERYX 11, SMIB 10

1. The composition of sterol mixture from the “living fossil” crinoid Gymnocrinus richeri collected off Nouméa (New Caledonia) was investigated. The free 3P-OH sterol mixture was found to contain 14 components, A: and ring saturated stanols, identified .by GC-MS. 3. Cholest-4-en-3-one, cholesta-1, 4-dien-3-one (this latter firstly isolated from a marine source), 5cr-8a-epidioxy sterols, and 5a-ergosta-7,22-diene-3/?,5,6j-triowl ere also present, their characterization being accomplished by EI-MS and ‘H-NMR. The methanol extract also contained sterol sulphates, which were identified by GC-MS after solvolysis to remove the sulphate group.

CALSUB

Five novel brominated phenanthroperylenequinone pigments, gymnochromes A-D (1-4) and isogymnochrome D (5), were isolated from the stalked crinoid Gymnocrinus richeri. The structures of the compounds were inferred from their spectra (IR, UV-vis, H-1 and C-13 NMR, FABMS). The presence of both bulky hydroxy groups at positions 10 and 11 and side chains at positions 3 and 4 causes sufficient crowding to force the octacyclic phenanthroperylenequinone system into a nonplanar helical shape. This helicity generates axial chirality in the molecules. The presence of chiral carbon atoms in the side chains gives rise to diastereomers. The absolute configurations of the chiral carbons and the axial chirality of the natural pigments was inferred from CD and NMR data and by correlations made with cercosporin and other naturally occurring perylenequinones. The configurations assigned to the chiral carbons in the side chains of compounds 4 and 5 were confirmed by the results of the application of Horeau's method of kinetic resolution.

CHALCAL 2

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Beside tremasterols A-C, first phosphated steroid glycosides to be found from a natural source, the starfish Tremaster novaecaledoniae contains nine more novel steroid constituents. One, 4, is related to the previous tremasterols by having the same 6-O-phosphated function. A secound of compounds (5-8) possesses the same 3,6-disulphated 3 beta, 6 alpha, (22R)- trihydroxycholestane structure, differing for the presence of the delta 9 double bond in 5 and 6 and for the acetate conjugation of the 22-hydroxyl group in 6 and 8. The remaining compounds 9-12 are highly hydroxylated steroids, among which the steroids 11 features the cis A/B ring junction, never encountered before among steroids derived from starfishes.

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Le benthos profond récolté tout d'abord lors des campagnes océanographiques MUSORSTOM IV (1) et CHALCAL (2), puis lors des campagnes de récoltes SMlB (1986, 1987, 1989) s'est avéré être extrèmement riche en invertébrés divers dont beaucoup sont nouveaux. L'abondance et l'originalité de cette faune nous a conduit à étudier une cinquantaine d'organismes recoltés entre 200 et 700m: éponges (40), échinodermes (1 O), alcyonaires (2), madréporaires (1).

CHALCAL 1, MUSORSTOM 4

Two polynitrogen compounds 1-methyl-pteridine-2,4-dione 1b and corallistine 2 were isolated from new-caledonian sponge Corallistes fulvodesmus L. & L. The structure of corallistine was determinated by X-ray single cristal analysis of its 6'-isobutyloxycarbonyl derivative 3.

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Ten novel polyhydroxylated 9,ll-secosterols, 1-10, have been isolated from the New Caledonian sponge Euryspongiu sp. and their structures elucidated by spectroscopic studies, selcctive acetylation and reduction, leading to the complete assignment of all the NMR signals. Euryspongiols Al-A5 differ in their side chains but have the same 2a,3ß,4a,6ß,11,19 hexahydroxy-9,ll-secocholestane skeleton. Euryspongiols B 1-B5 are the corresponding 3a epimers. Compounds 1-10 are the most highly hydroxylated secosteroids isolated so far, and are the first hydroxylatcd at C4. NaBH4 reduction of the carbonyl group at C-9 of 1 and 2 is stereospecific, producing the heplahydroxylated secosteroids la and 2b with a ß C-9 hydroxyl group. Compounds 1 and 2 have been found to strongly inhibit the release of histaminc from rat mastocysts.

VAUBAN 1978-1979

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Along with two known cheilanthane sesterterpene lactones, 1 and 2, eight new related sesterterpenes (3-10) and two new nor-sesterterpenes (11 and 12) have been isolated from the New Caledonian marine sponge Petrosuspongia nigra Bergquist 1995 (new genus, new species). Their structures were determined from 1D and 2D NMR studies and mass spectral data. They exhibited cytoxicity against the NSCLC-N6 human bronchopulmunary non-small-cell-lung carcinoma cell lines.

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The sponge Stelletta sp. (Astrophorida, Stellettidae), collected at - 700 m in the Coral Sea, is shown to contain sterones and sterols of the stigmastane type with a C(24) = C(25) bond for which there is no precedent in the sea. Structure elucidation of the second abundant of these steroids, stigmasta-4,24(25)-dien-3-one((+)-1), is based on 1D and 2D NMR spectra and chemical transformation to acetate (-)-5. Stigmasta-4,24(25)-diene-3,6-dione ((-)-3), present in trace amounts in the sponge, was obtained in sufficient quantity for NMR study by oxidation of the also present, inseparable, and abundant 4:1 mixture of stigmasta-5,24(25)-dien-3-beta-ol (6) and its 5,6-dihydro derivative 7 (Scheme 1). This oxidation also afforded the ketone analogues (+)-8 and (+)-9, which could be separated, thus making structure elucidation possible. The 6-beta-hydroxystigmasta-4,24(25)-dien-3-one ((+)-4), also present in trace amounts in the sponge, was obtained in sufficient amount for NMR study, together with its C(6) epimer (+)-11, by hydroperoxidation of (+)-8 followed by deoxygenation (Scheme 2). The last trace steroid of the sponge, stigmasta-4,6,24(25)-trien-3-one ((-)-2), was structurally elucidated using limited NMR data and comparison with the other stigmastanes. These stigmastanes, as the only steroids of this sponge, are likely to function as stabilizers of its cell walls; their phytosteroid structure, for a sponge which lives in the dark of deep waters, suggest origin through a complex food chain, possibly followed by bioelaboration in the sponge.

CORAIL 2

The lithistid sponge Corallistes undulatus, which inhabits the base (- 510 m) of the New Caledonian coral reef, is shown here to contain the pteridines 1-methylpteridine-2,4- dione, already known from another Corallistes, and the new(1'R,2'S)-6-(1',2'-dihydroxypropyl)- 1-methylpteridine-2,4-dione together with the steroids 3ß-hydroxy-24- methylenecholest-5-en-7-one, 7-ALPHA-hydroxysitosterol,7ß -hydroxysitosterol, and 3ß-hydroxystigmast-5-en-7-one, typical of higher terrestrial plants, and the indole derivatives methyl(2E)-3-(indol-3-yl)-2-propenoate, methyl(2E)-3-(6-bromoindol-3-yl)- 2-propenoate, and serotonin. The presence of the same compounds in taxonomically, phyletically, and ecologically unrelated organisms is viewed here as resulting from evolutionary convergence toward adaptive products.

SMIB 4, SMIB 5

Aztequynol A (1), isolated from the nepheliospongid sponge, Petrosia sp., from the Banc Azteque off New Caledonia, represents the first case of a structurally defined C-branched polyacetylene based on high-energy collisionally-activated decomposition tandem mass spectrometry of lithium adducts which may have wide application in natural product structural analysis.

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Ten marine polyhydroxysteroids, 1-10, of which two, 1 and 5, are known compounds previously isolated from starfish, have been isolated from the deep water starfish Styracaster caroli, collected at a depth of 2000 m off New Caledonia. The 3ß,5,6ß-trihydroxy functionality is the common element in these steroids, and additional hydroxylgroups were found at positions 8,15a (or ß) and lbß. Greater differences are observed in the structure of the sidechains, which showed multiple functionalities and different alkylationpatterns. Characterization was accomplished by fabms and 'H- and "C-nmr spectroscopy, with the assignments of the configurations to the stereogenic centers of the side-chains being made by 'H-nmr comparison with appropriate models and on analysis of their derivatives with a chiral reagent.

BIOGEOCAL

Two new alkaloids, phloeodictine A (1) and phloeodictine B (21, possessing an unprecedented 6-hydroxy- 1,2,3,4 tetrahydropyrrolo[ 1,2-a]pyrimidinium skeleton have been isolated from an undescribed species of the deep sponge Phbeodictyon. The structures were determined by extensive spectroscopic analysis particularly two-dimensional NMR experiments. Both compounds exhibited in vitzo antibacterial activity against Gram-positive and Gram-negative bacteria and were moderately cytotoxic against KB cells.

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Metabolites isolated from marine inverte-brates, callipeltin A 1, crambescidin 2, ptilomycalin A 3,celeromycalin 4, gymnochrome B 5, gymnochrome D 6 and isogymnochrome D 7 previously shown bioactive on either herpes simplex virus 1 (2, 3, 4) or human immunodeficiency virus (1, 5, 6, 7), were tested on a new in vitro bioassay using the dengue virus 1. Only gymnochrome D and isogymnochrome D isolated from the living fossil crinoid Gymnocrinus richeri are highly potent dengue antiviral agents.

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Six new dendrolasin-type hydroxylated sesquiterpenes have been isolated from the cytotoxic extracts of the marine tunicate Ritterella rete. The absolute stereochemistry of the new compounds was determined by a combination of spectroscopic and chemical correlations, including derivatization with a recently introduced NMR reagent. This is the first time furanoterpenes have been isolated from a marine tunicate.

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The antiproliferative activity of two nitrogenous labdane cytotoxic substances from Lissoclinum voeltzkowi Michaelson (Urochordata), dichlorolissoclimide (P2) and chlorolissoclimide (P1), was studied in vitro on a continuous human non small- cell bronchopulmonary carcinoma line (NSCLC-N6) at the cell cycle level. This antiproliferative effect resulted from a blockade of G1 phase cells. Mortality occurred, regardless of the degree of cell ploidy, with cell transition to an out-of-cycle situation characteristic of a G1D terminal maturation state.

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Nortopsentin D (S), a bis(indo1e) alkaloid unique for bearing a 2-amino-methylimidazole appendage at the central lH-imidazol-5(4H)-one nucleus, was isolated in abundance, besides the putative biogenetic precursor 6 of its appendage, from the deep-water axinellid sponge Dragmacidon sp. Structural elucidation of 5 by NMR and MS methods heavily relied on its N-methyl derivatives 8-11. Unusually for topsentin-type structures, natural 5 and semisynthetic methyl derivatives 8 and 10 proved inactive on KB tumoural cells, while introduction of the last three methyl groups, amazingly led to highly cytotoxic 11.

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Three new manoalide-related sesrerrerpenes. fasciospongides A [1], B [2], and C [3], have been isolated from the sponge Fasciospongia sp. and their structures elucidated by spectral methods.

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One known drimane sesquiterpene (1) and five new ones (2-6) have been isolated from the sponge Dysidea fusca. Their structures were elucidated mainly by 2D NMR. The relative stereochemistry at C-11 of 1 has been corrected to H-11 beta.

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The sponge Neosiphonia supertes contains 24(28)-dehydroaplysterol [1] and the new steroid (25S)-26-methyl-24-methylenecholest-4-en-3-one [2].

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The complete absolute stereochemistry of two new cytotoxic marine polypropionaies isolated from the saponified extract of the pulmonate mollusc Onchidium sp., onchitriol I and II (4, 5)was established using Mosher-Trost's methodology.

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The structure and absolute configuration (3R, 17R) of the indole alkaloid arborescidine C were determined by x-ray diffraction. The six-membered ring assumes a half-chair conformation and the seven-membered ring has a twist-like conformation. The crystal packing is characterized by intermolecular hydrogen-bonding between the hydroxyl group and nitrogen atom N4 which leads to the formation of infinite chains of molecules along the a-axis of the crystal. The absolute configurations of two related indole alkaloids, arborescidine B and arborescidine D are inferred from the experimentally determined configuration of arborescidin C molecule. A comparison of the present structure with that of a related indole alkaloid akagerine showed significant conformational and configurational differences. Crystal data: C16H19N2OBr, orthorhombic, P21212, a = 10.3376(8), b = 15.461(4), c = 9.2094(9)A, V = 1471.9(6)A3, Z = 4, Dcalc = 1.510 g cm-3, A = 1.54178A.

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A cytotoxic glycoside macrolide, callipeltoside A, has been isolated from the marine lithistid sponge Callipelta sp., collected off New Caledonia. Structural assignent was accomplished through extensive 2D NMR spectroscopy. The complete relative stereochemistry is proposed from the analysis of ROESY and NOE difference experiments. Callipeltoside A (1) represents the first member of a new class of marine-derived macrolides, containing unusual structural features including a 4-amino-4,6-dideoxy-2-0,3-C-dimethyl-& talopyranosyl-3,4-urethane unit.

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Following the characterization of callipeltoside A (1), the first member of a novel class of marine glycoside macrolides, two more bioactive constituents, callipeltoside B (2) and C(3), were isolated from Callipelta sp. in very low amounts. The structures, assigned on the basis of spectral analysis, include the same 14-membered macrolide as in callipeltoside A (1) but differed in the saccharide moieties.

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