121007-17-8Relevant articles and documents
Synthesis and structure - Phytotoxicity relationships of acetylenic phenols and chromene metabolites, and their analogues, from the grapevine pathogen Eutypa lata
Smith, Leverett R.,Mahoney, Noreen,Molyneux, Russell J.
, p. 169 - 176 (2007/10/03)
Eutypa lata, the fungus responsible for dying-arm disease in grapevines, produces a number of structurally related secondary metabolites, of which eutypine (1) has been implicated as the principal phytotoxin. However, analysis of an E. lata strain from California known to be pathogenic to grapevines showed that eutypine was not present, suggesting that other metabolites could be phytotoxic. Investigation of the relative phytotoxicities of individual metabolites has been limited by insufficient material and lack of a reliable bioassay. Metabolites of particular interest and their precursors were therefore synthesized, and a rapid, quantitative bioassay via topical application of individual compounds to disks of grape leaves and measurement of chlorophyll loss was developed to provide a relative measure of tissue damage. The recently reported metabolite eulatachromene (2) was found to have phytotoxicity greater than that of eutypine (1). The cyclization product, 5-formyl-2-methylvinyl[1]benzofuran (3), also showed significant activity, whereas the reduction product, eutypinol (4), was inactive, as was the quinol, siccayne (5). These results indicate that before strains of Eutypa are incriminated as pathogenic they must be analyzed for the presence or absence of specific constituents for which the phytotoxicity has been unequivocally established.
New Synthetic Applications of Water-Soluble Acetate Pd/TPPTS Catalyst Generated in Situ. Evidence for a True Pd(0) Species Intermediate
Amatore, Christian,Blart, Errol,Genet, Jean Pierre,Jutand, Anny,Lemaire-Audoire, Sandrine,Savignac, Monique
, p. 6829 - 6839 (2007/10/03)
Studies on the sp-sp intermolecular coupling reactions with the palladium water-soluble catalyst prepared in situ from palladium(II) acetate and sulfonated triphenylphosphine P(C6H4-m-SO3Na)3 (TPPTS) in a homogeneous acetonitrile-water system, without Cu(I) promotor, afford diynes with moderate yields (45-65percent).Under the same conditions, the sp2-sp coupling of 2-iodophenols or 2-iodoanilines and terminal alkynes followed by intramolecular cyclization gives indolic and furanic products in good yields (60-99percent).Under these aqueous conditions, an efficient and short synthesis of eutypine illustrated the synthetic potentiality of the coupling.Furthermore, through a series of kinetic and 31P NMR experiments, we have demonstrated that a mixture of Pd(OAc)2 and TPPTS affords spontaneously a palladium(0) complex, through formation of bivalent complex Pd(OAc)2(TPPTS)2.A detailed mechanism of the reaction has been investigated thoroughly and the pertinent rate constants measured.The resulting palladium(0) complex reacts with phenyl iodide via an oxidative addition.This complex is considerably less reactive than the corresponding complex generated from PPh3, probably due to steric effects.
