Stenotarsol, a new terpenoid from Stenotarsus subtilis (Coleoptera: Endomychidae)

Stenotarsol (1), a new terpenoid alcohol, has been isolated from the beetle Stenotarsus subtilis (Endomychidae). Its structure has been determined on the basis of its spectral properties. Compound 1 represents a new type of terpene skeleton and is the first secondary metabolite reported so far from this family of beetles.     

Preparation and characterization of MgB2 superconductor

The MgB₂ superconductor, synthesized using solid-state and liquid-phase sintering methods, have been characterized for various properties. The upper critical field, irreversibility line and critical current density have been determined using magnetization data. The current-voltage characteristics recorded under an applied magnetic field revealed the existence of vortex glass transition. The surface analysis using X-ray photoelectron spectroscopy shows that MgB₂ is sensitive to atmospheric degradation.     

New macrolactones from the defensive salivary secretion of soldiers of the african termite Pseudacanthotermes spiniger

The salivary defensive secretion of large soldier termites of the species Pseudacanthotermes spiniger contains two novel macrocyclic lactones [22-keto-hexacosanolide (2) and 2-hydroxy-24-keto-octacosanolide (3)] together with the already known macrolactone hexacosanolide (1). In addition, the secretion contains important amounts of a polysaccharide based mainly upon β-glucopyranose, β-glucosamine and N-acetyl-β-glucosamine in equal amount.     

Chemical studies of marine invertebrates—XLII: The relative and absolute configuration of dysidenin

The relative and absolute configuration of dysidenin has been determined by chemical correlation between dysidenin, isodysidenin and their respective dechlorinated derivatives.