Structure/Odor Relationships of (&sminus 0;)- and (&splus 0;)-β-Vetivone,and Their Demethyl Derivatives

(−)-β-Vetivone ((−)- 3a ), one of the main constituents of vetiver oil, was submitted to a structure/odor relationship study. The influence of the Me groups at the cyclohexenone ring and of the configuration on the odor was examined. Detailed ¹H- and ¹³C-NMR-spectroscopic data were collected, and the absolute configurations were determined by CD methods.     

Poly(phenylsilsesquioxane)s: Structural and morphological characterization

Poly(phenylsilsesquioxane) (PPSQ) polymers that were obtained from different synthetic routes were comparatively studied. The polymers were characterized by infrared and solid‐state ²⁹Si NMR spectroscopies. According to the results of X‐ray diffraction and thermogravimetric analyses, the materials richest in silanol showed a less organized network and lower weight loss temperature. The morphology of the products was influenced by the preparation conditions. PPSQ, with a morphology rich in spherical particles, was achieved with an n‐hexadecyltrimethylammonium bromide template in the reaction medium, whereas the morphology of this polymer obtained in the absence of the template was featureless. Small‐angle X‐ray scattering analyses revealed that the PPSQ samples showed a predominance of surface‐fractal behavior. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1580–1589, 2000     

Cytotoxicity of tantalum(V) and niobium(V) small carborane complexes and mode of action in P388 lymphocytic leukemia cells

The metallacarboranes (Et₂C₂B₄H₄)‐­TaCl₂(C₅H₅) ( 1 ), (Et₂C₂B₄H₄)NbCl₂(C₅H₅) ( 2 ), (Et₂C₂B₄H₄)TaCl₂(C₅Me₅) ( 3 ), [(Me₃Si)₂­C₂B₄H₄]TaCl₂(C₅H₅) ( 4 ) and (Me₂C₂B₄H₄)‐­TaCl₂(C₅H₅) ( 5 ) are potent cytotoxic agents against suspended tumors, producing cell death in several tissue culture lines; for example, all were effective against murine L1210 lymphoid leukemia, and all except 5 against murine P388 lymphocytic growth. Human leukemic growth is also retarded since 1–4 were effective against Tmolt₃ cell leukemia, all except 4 against Tmolt₄ leukemia, and 1, 2 , and 5 against HI‐60 leukemia. Cytotoxicity was found towards HuT‐8 lymphoma, THP‐1 acute monocytic leukemia and suspended HeLa‐S³ uterine carcinoma. Some but not all of the complexes were active against Sk‐2 melanoma and Mcf‐7 breast effusion growth. Mode‐of‐action studies in P388 lymphocytic leukemia cells showed that de novo purine synthesis was inhibited; this inhibition reduces DNA and RNA syntheses. Purine synthesis was reduced by compounds 3 and 4 at the regulatory enzymes, i.e. phosphoribosyl pyrophosphate (PRPP) amidotransferase and dihydrofolate reductase. The agents lowered d[ATP] and d[CTP] pools, further reducing DNA synthesis. The complexes afforded DNA fragmentation leading to apoptosis, but this was not by a mechanism of nucleoside alkylation, intercalation between base‐pairs or cross‐linking of the DNA strands. Copyright © 2000 John Wiley & Sons, Ltd.     

Selective Targeting of Lymphoma Cells by Monoclonal Antibody Grafted onto Zwitterionic-Functionalized Nanoparticles

Nanomedicine is considered a promising alternative to improve cancer diagnosis and treatment. Particularly, the use of nanoparticles (NPs) has enabled the encapsulation of highly toxic anticancer drugs, facilitated ultimate targeting, and allowed tailoring of drug delivery. However, when in biological fluids, these NPs are coated by proteins which hide the targeting moieties and suppress the engineered biological outcome. Herein, how the Ki-1 monoclonal antibody (mAb) can preserve its targetability through grafting on the surface of zwitterionic-functionalized nanoparticles, is unveiled. Zwitterions, known for their stealth ability, are used to minimize unspecific NPs protein adsorption and consequently maintain mAb functionality. In this work, Ki-1 mAb is used as it recognizes TNFRSF8 (CD30⁺) transmembrane protein overexpressed on CD30⁺ lymphoma cells such as L540 cells. While nonfunctionalized NPs show negligible toxic effects toward L540 cells, the Ki-1-functionalized structure demonstrates cytotoxicity, since they undergo cellular uptake, suggesting a receptor-mediated internalization. This dual-functionalization strategy provides a promising multifunctional nanoplatform toward future personalized medicine applications, minimizing unspecific protein adsorption on NPs and ensuring selective cancer cell targeting.     

Zweifach und dreifach intramolekular verbrückte p‐tert‐Butylcalix[8]aren‐triphosphate – Synthese,Struktur und Stereochemie

Two‐ and Threefold Intramolecular Brigdging p‐tert‐Butylcalix[8]arene Triphosphates – Synthesis, Structure and Stereochemistry [1] The phosphorylation of p‐tert‐butylcalix[8]arene ( 1 ) with phosphorus pentachloride and hydrolysis gives intramolecular bridging tert‐butylcalix[8]arene triphosphates. The reactivity (esterification, dehydratisation, complexation), the structure (nmr and x‐ray), and the stereochemical behaviour of the phosphates will be discussed.     

13C‐NMR spectra of santalol derivatives: a comparison of DFT‐based calculations and database‐oriented prediction techniques

A systematic investigation of a series of santalol and epi‐santalol derivatives by means of ab initio and density functional theory (DFT) calculations together with database‐oriented prediction methods leads to a configurational reassignment within this compound class. The DFT calculations as well as the HOSE‐code and neural network‐based predictions allow deriving a general rule set for unambiguous assignment within this compound class. The methyl group in position 2′ serves as an indication for the configuration at this stereocenter allowing easy differentiation between santalol derivatives and their diastereomers belonging to the epi‐santalol series. Copyright © 2009 John Wiley & Sons, Ltd.