2015-09-0Relevant articles and documents
Shape dependent catalytic activity of nanoflowers and nanospheres of Pd4S generated via one pot synthesis and grafted on graphene oxide for Suzuki coupling
Singh, Ved Vati,Kumar, Umesh,Tripathi, Sandeep Nath,Singh, Ajai Kumar
, p. 12555 - 12563 (2014)
Nanoflowers and nanospheres of Pd4S have been prepared for the first time from a single source precursor complex, [PdCl2(PhS-CH 2CH2CH2-NH2)] (1), by its one pot thermolysis at 195 °C. In oleylamine, flower shaped nanoparticles of Pd 4S were formed but in an oleic acid (OA) and octadecene (ODE) mixture (1:1) the product was nanospheres of Pd4S (size in the range ～23-38 nm and 15-28 nm, respectively). These nanoparticles (NPs) were grafted on graphene oxide (GO) at room temperature to prepare nanocomposites, GO-Pd4S. HRTEM, powder X-ray diffraction (PXRD) and TEM-EDX have been used to authenticate the nanoparticles and their composites. XPS of Pd 4S NPs indicates the oxidation states of Pd and S are both zero with a Pd:S ratio ～4.1:0.9. For the catalysis of Suzuki-Miyaura coupling reactions the nanoparticles individually and in the form of composites with GO were explored. The flower shaped NPs are superior than the spherical ones for this catalysis in aqueous ethanol and the catalytic efficiency increases on grafting the nanoflowers/spheres onto GO. The conversion was ～99% (in 5 h; at 80 °C) for the composite of graphene oxide (GO) with the Pd4S nanoflowers (Pd: 0.2 mol%). The catalytic efficiency follows the order GO-Pd4S-nanoflowers > GO-Pd4S-nanospheres > Pd 4S nanoflowers > Pd4S nanospheres. The recyclability of the GO-Pd4S nanoflower catalyst was examined for the coupling reaction and conversion was found to be ～46% in the fourth run even after increasing the reaction time to 12 h. To understand whether the catalytic process with the GO-Pd4S nanoflowers was homogeneous or heterogeneous mercury poisoning, triphenylphosphine and three phase tests were carried out. They suggest that active Pd leached from GO-Pd4S nanoflowers does the catalysis significantly in a homogeneous fashion. Overall the catalysis appears to be a cocktail of homogeneous and some heterogeneous nature. This journal is the Partner Organisations 2014.
Inhibition of adhesion molecule expression by N-alkylthiopyridine-benzo[b]thiophene-2-carboxamides
Boschelli, Diane H.,Connor, David T.,Lesch, Mark E.,Schrier, Denis J.
, p. 557 - 562 (1996)
The surface levels of ICAM-1 and E-selectin on activated endothelial cells can be reduced by 3-alkoxybenzo[b]thiophene-2-carboxamides. This property is shared by several N-alkylthiopyridine substituted imides. Combining structural elements of these two diverse series lead to a new class of small molecule inhibitors of adhesion molecule expression.
Synthesis of (+)-Lentiginosine and Its Pyrrolizidine Analogue Based on Intramolecular Cyclization of α-Sulfinyl Carbanions
Du-A-Man, Sakkarin,Soorukram, Darunee,Kuhakarn, Chutima,Tuchinda, Patoomratana,Reutrakul, Vichai,Pohmakotr, Manat
, p. 1708 - 1715 (2015/10/05)
A synthesis of (+)-lentiginosine and its pyrrolizidine analogue was accomplished in six steps, starting from L-(+)-tartaric acid. The key step of these syntheses involves the intramolecular cyclization of α-sulfinyl carbanions for the construction of the indolizidine or pyrrolizidine ring.
General method for synthesis of erythrinan and homoerythrinan alkaloids (2): Application of pummerer-type reaction to the synthesis of homoerythrinan ring system
Toda, Jun,Niimura, Yoshihiro,Sano, Takehiro,Tsuda, Yoshisuke
, p. 1599 - 1607 (2007/10/03)
The synthesis of cyclohomoerythrinan (2a), a potential intermediate to homoerythrinan alkaloids, was achieved by a Pummerer-Type cyclization of the hydroindole sulfoxide (11), which was prepared from the dioxopyrroline (6) in five steps via a [2+2] photocycloaddition reaction followed by an anionic 1,3-shift.
