Etude comparative de la photoreactivite d'enamides et de thioenamides aromatiques tertiaires

Photolytic reactions of some simple aromatic enamides and thioenamides illustrate a novel example of the dramatic difference in the photochemical behaviour of carbonyl and thiocarbonyl compounds. In contrast with their oxo-analogues which are photoconverted into enaminoketones, thioenamides undergo photochemical cyclization to yield isoquinolinethione derivatives which can be easily converted into isoquinolones and tetrahydroisoquinolines.     

A Convenient Synthesis of Functionalized α‐Methylidenebutano‐4‐lactams

A concise synthetic approach to functionalized α‐methylidenebutanolactams has been developed. The synthetic strategy is based on the preliminary assembly of the lactam template equipped with appropriate functionalities. Subsequent installation of the methylidene by a metalation/alkylation/elimination sequence completed the elaboration of the racemic title compounds.     

Kinetics of RAFT homopolymerisation of vinylbenzyl chloride in the presence of xanthate or trithiocarbonate

The RAFT homopolymerisation of vinylbenzyl chloride (VBC, or chloromethyl styrene CMS) in bulk and in acetonitrile initiated by α,α′-azoisobutyronitrile (AIBN) in the presence of two chain transfer agents, O-ethyl-S-(1-methyloxycarbonyl)ethyl xanthate and dibenzyl trithiocarbonate, is presented. The reactions were monitored by ¹H nuclear magnetic resonance spectroscopy in the presence of 1,2-dichloroethane as the internal standard. Such a technique enabled one to assess the evolutions of log ([M]₀/[M]) and VBC conversion vs. time that were shown to be linear. Tobolsky’s law allowed one to determine the square of the propagation rate constant to the termination rate constant, $k_{\text{p}}^2/k_{\text{te}}$, of VBC, that worths about 3 × 10^?3 l mol^?1 s^?1 at 80 °C. On the one hand, the controlled character of the polymerisation involving dibenzyl trithiocarbonate was confirmed by size exclusion chromatography. On the other hand, the molar masses of poly(VBC) polymerised in the presence of the xanthate agent decreased with monomer conversion, as already stated with the macromolecular design via interchange of xanthates (MADIX) polymerisation of styrene.     

Anthracene-tethered ruthenium(II) arene complexes as tools to visualize the cellular localization of putative organometallic anticancer compounds

Anthracene derivatives of ruthenium(II) arene compounds with 1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane (pta) or a sugar phosphite ligand, viz., 3,5,6-bicyclophosphite-1,2-O-isopropylidene-α-d-glucofuranoside, were prepared in order to evaluate their anticancer properties compared to the parent compounds and to use them as models for intracellular visualization by fluorescence microscopy. Similar IC(50) values were obtained in cell proliferation assays, and similar levels of uptake and accumulation were also established. The X-ray structure of [{Ru(η(6)-C(6)H(5)CH(2)NHCO-anthracene)Cl(2)(pta)] is also reported.     

A new total synthesis of porritoxin

A concise and efficient total synthesis of the phytotoxin porritoxin is described. The key step of the synthesis is based upon a Parham cyclization methodology which enables the creation of the lactam unit embedded in the title compound framework with the concomitant formation of the tethered hydroxyakyl chain.