Phthalonimides (1,3,4-trioxo-1,2,3,4-tetrahydroisoquinolines) of potential biological interest

A new simple method for the preparation of phthalonimides (1,3,4-trioxo-1,2,3,4-tetrahydroisoquinolines), consisting of the selenium dioxide-oxidation of the appropriate homophthalimides, has been devised; the thiosemicarbazones and other derivatives of phthalonimides of possible biological interest (as potential antibacterial, antiviral, or immunosuppressive agents) have been synthesized.     

Cycloaddition reactions of thiiranimines

Thiiranimines have been found to cycloadd by the three pathways shown in Scheme 1. The reactions are examplified with enamines (path a), ynamines (path b) and aldehydes (path c).     

Structural analysis of mycobacterial lipoglycans

Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the most effective human pathogens. The mycobacterial cell envelope contains lipoglycans, and of particular interest is lipoarabinomannan (LAM), one of the most potent mycobacterial immunomodulatory molecules. The importance of lipoarabinomannan (LAM) in the immunopathogenesis of tuberculosis has incited structural studies on this molecule to (1) establish a precise structural model of the molecule and (2) decipher the structure/function relationships. In recent years, we have focused on the two domains essential for LAM biologic activities: the mannosyl-phosphatidyl-myo-inositol anchor and the caps. We review here the recent procedures developed for the structural analysis of these domains.     

Snake-based method for the segmentation of objects in multichannel images degraded by speckle

We recently proposed a new approach for the segmentation of speckled images based on active contours (snakes) [e.g., Opt. Commun. 137, 382 (1997)]. We propose an extension of this approach to multichannel data. Two solutions are compared based on hypotheses on the possible mean intensity variation between the channels. Each solution is optimal for a certain class of input images, but one solution shows better or equivalent performance for both input image classes. This result opens new perspectives for the segmentation of multichannel images with the snake-based approach.     

Secotrinervitane,a novel bicyclic diterpene skeleton from a termite soldier

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.