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Research has been conducted on the cyclobutenbriarein A, a diterpene possessing a tricyclo[8.4.0.0 (super)3,6]tetradec-4-ene ring system. The isolation of this diterpene from Briareum asbestinum organic extracts has been carried out and investigated and the details are reported.

Onchidin B is a cyclic depsipeptide isolated from the pulmonate mollusc Onchidium sp. Its structure was determined by extensive 2D-NMR, FABS, tandem FAB MS/MS, selective hydrolysis and synthesis. It has four alpha-amino acids, four alpha-hydroxy acids and two units of the new beta-hydroxy acid. The lack of symmetry of onchidin B was found to be caused by the presence of one (S)-Pro unit in one half and one (R)-Pro unit in the other.

The union of xestoquinolide A and B quinones, which belong to the polycyclic quninones and hydroquinoues of the halenquinone class isolated from two IndoPacific collections of the sponge Xestopongia cf. carbonasia, can be used to biogenetically obtain the halengafamily which does not seem to be of polypeptide origin. Xestoquinolide A and B, 14-methoxyhalenaquinone and tetrahydrohalenaquinone B were among the four new metabolites that were characterized.

The South Pacific mollusc Onchidium sp. yields onchitriols I A-D and II A-D, each bearing two gamma-pyrones within a 19-membered 6,15-dioxoalken-9-yl chain. Spectroscopic studies establish their molecular formulas as C36H52O2 (IA), C37H54O9 (IB and IC, isomers at C-11/C-13), C40H58O10 (ID), C34H50O8 (IIA), C35H52O8 (IIB), C38H54O10 (IIC) and C36H52O9 (IID). On saponification, I A-D yields the deesterified onchitriol I (C32H48O7)while II A-D yield the deesterified onchitriol II (C32H48O7). Trost-Mosher mandelation sets the absolute configuration of onchitriol I as 3S,4S,10S,13R,14R,15R,16R and that of onchitriol II as 3S,4S,10R,13S,14R,15R,16R.

A study conducted on tunicate Didemnum sp. collected in Sulawesi Island, Indonesia, resulted in the isolation and structural characterization of the first group of serinolipids from a marine organism. The serinolipids, which have been designated as didemniserinolipids A, B and C, are 2-amino-1,3-propanediols that are linked to a hydroxylated alpha, beta-unsaturated acid that have an unusual 6,8-dioxabicyclo(3.2.1)octane structure.

A new strategy for the J-based configurational analysis in acyclic systems is applied where the existence of multiple conformer equilibrium has precluded the application of the Murata methodology.

Three unusual new steroid thioesters, parathiosteriods A-C were isolated from the 2-propanol extract of the soft coral Paragorgia sp. collected in Madagascar. Their structures represent the first isolation of natural steroids bearing a C22 thioester in their side chain.

Xestocyclamine A is a polycyclic alkaloid protein kinase C (PKC) inhibitor. Semipure extracts of Xestospongia sp., a soft, brown massive sponge shows total inhibition against PKC-beta at 5 micrograms per milliliter. Regular or reversed phase HPLC of active fractions produces impure mixtures, and this reveals that purification is not direct.

Investigates the ring system of cyclobutenbriarein A, a C20-rearranged diterpene briarane from the Gorgonian Briareum asbestinum. Terpene metabolites of the gorgonians; Nucleophilic substitution of chorine to yield cyclobutenbriarein; Structural elucidation of diterpenes.

Explores the isolation and the structural elucidation of the first serinolipids from a marine organism extract. Isolation of didemniserinolipids A-C, unprecedented serinolipids from the Turnicate didemnum sp.; Isolation of 2-amino-1,3-propanediols linked to a hydroxylated alpha,beta-unsaturated acid.

The kinetics for the decomposition of the symmetrical proton-bound dimers of a series of 2-ketones (M) from acetone to 2-nonanone have been determined at ambient pressure by linear ion mobility spectrometry (IMS) and by differential mobility spectrometry (DMS). Decomposition, M2H(+) →MH(+) + M, in the IMS instrument, observed under thermal conditions over the temperature range 147 to 172 °C, yielded almost identical Arrhenius parameters Ea = 122 kJ mol(-1) and ln A = 38.8 for the dimers of 2-pentanone, 2-heptanone, and 2-nonanone. Ion decomposition in the DMS instrument was due to a combination of thermal and electric field energies at an effective ion internal temperature whose value was estimated by reference to the IMS kinetic parameters. Decomposition was observed with radio frequency (RF) fields with maximum intensities in the range 10 kV cm(-1) to 30 kV cm(-1) and gas temperatures from 30 to 110 °C, which yielded effective temperatures that were higher than the gas temperature by 260° at 30 °C and 100° at 110 °C. There was a mass dependence of the field for the onset of decomposition: the higher the ion mass, the higher the required field at a given gas temperature, which is ascribed to the associated increasing heat capacity with the increasing carbon number, but similar, internal vibrations and rotations.