In vitro blood compatibility evaluation method: incubating while rotating hemodialyzers filled with fresh human blood.

One of the often-used methods for in vitro evaluation of the blood compatibility of hemodialysis membranes is the circulation of human blood through a miniaturized hemodialyzer. The use of a rather small amount of human blood in its evaluation is one advantage of this method. However, because it is manufactured by a different process than actual ones, a miniaturized hemodialyzer membrane cannot always preserve the properties of actual hemodialyzers. To address this problem, we established a new experimental method that uses a relatively small amount of human blood and actual dialyzers. In this method, a test hemodialyzer and a control hemodialyzer filled with human blood obtained from the same donor is slowly rotated to prevent spontaneous blood cell sedimentation for 4 h at 37 °C. By use of this method, we were able to compare blood compatibility between a polysulfone (PS) membrane and a vitamin E (VE)-bonded PS membrane in terms of their relative antithrombotic, antioxidative, and anti-inflammatory properties. Consistent with many previous reports, the results clearly showed that compared with the PS membrane, VE-bonded PS membrane is more blood compatible. These findings suggest that our method is applicable, at least to in vitro blood compatibility evaluation of PS type dialysis membranes.

Gold(I)-Catalyzed Cascade Cyclization of Anilines with Diynes: Controllable Formation of Eight-Membered Ring-Fused Indoles and Propellane-Type Indolines.

Heterocycle-fused indoles or indolines are distributed widely in a variety of natural products, bioactive agents, and pharmaceuticals. Herein, we describe the development of gold-catalyzed cascade reactions of anilines with diynes to form eight-membered ring-fused indoles and propellane-type indolines, both of which proceed through an intramolecular 5-endo-dig hydroamination followed by an 8-endo-dig cycloisomerization. Controllable formation of eight-membered ring-fused indoles and propellane-type indolines was achieved through selection of the ligands and/or solvents. Protic solvents such as alcohols or IPr ligand favored the formation of eight-membered ring-fused indoles, whereas the use of Buchwald's type ligands and/or nonpolar solvents gave propellane-type indoline predominantly. This reaction provides rapid access to two types of fused nitrogen heterocycles from simple aniline derivatives.

Synthesis of Fused Carbazoles by Gold-Catalyzed Tricyclization of Conjugated Diynes via Rearrangement of an N-Propargyl Group.

Various N-propargylanilines bearing a conjugated diyne moiety at the 2-position were converted to tetracyclic fused carbazoles by treatment with a homogeneous gold(I) catalyst. This cascade reaction proceeds through indole formation with concomitant rearrangement of the N-propargyl group, intramolecular nucleophilic addition toward the resulting allene moiety, and subsequent hydroalkenylation. This transformation enables a one-pot synthesis of fused carbazoles from readily accessible substrates with 100% atom economy.

Gold-Catalyzed Cascade Cyclization of 2-Alkynyl-N-Propargylanilines by Rearrangement of a Propargyl Group.

Gold catalysis enables direct construction of tetracyclic fused indolines through the migration of a propargyl substituent from an aniline nitrogen atom to the C3-position of an indole from 2-alkynyl-N-propargylanilines. This reaction provides rapid access to fused three-dimensional indolines in a single operation with the formation of four bonds and three rings.

Dual gold catalysis: a novel synthesis of bicyclic and tricyclic pyrroles from N-propargyl ynamides.

Various N-propargyl ynamides were converted to bicylic and tricyclic pyrroles by the use of a cationic dual-activation gold catalyst. This reaction starts with the nucleophilic addition of a gold acetylide onto an ynamide triple bond at the ß-position of the nitrogen atom. Thus, gold vinylidene is formed, and then a second cyclization takes place. The formation of the gold vinylidene is indicated by the evidence that not only aryl ynamides but also alkyl ynamides undergo C-H activation in these reactions.

Dual gold catalysis: synthesis of polycyclic compounds via C-H insertion of gold vinylidenes.

New and interesting polycyclic compounds have been synthesized from non-conjugated diyne systems by dual gold catalysis. A quaternary carbon center in the backbone and the accompanying Thorpe-Ingold effect enabled the unprecedented insertion of sp(3) and sp(2) CH bonds that for the first time were incorporated within the backbone of the diyne system and allowed the construction of complex polycyclic carbon scaffolds inaccessible by previous approaches in which the CH bonds for the insertion were situated at the other end of the alkyne.

Gold-catalyzed cascade cyclization of (azido)ynamides: an efficient strategy for the construction of indoloquinolines.

(Azido)ynamides were efficiently converted into indoloquinolines by the use of a gold catalyst. While ynamides bearing an allylsilane gave terminal alkenes, ynamides bearing a simple alkene gave cyclopropanes. This reaction proceeds through the formation of an α-amidino gold carbenoid.

Wurster's Blue-type cation radicals framed in a 5,10-dihydrobenzo[a]indolo[2,3-c]carbazole (BIC) skeleton: dual electrochromism with drastic changes in UV/Vis/NIR and fluorescence.

Electron-donating dihydrobenzindolocarbazoles (BICs) 1 a-c, which adopt planar disk-shaped geometries, were prepared by gold(I)-catalyzed cyclization as a key step. Due to the presence of a 1,4-phenylenediamine (PD) moiety in the framework, they undergo reversible one-electron oxidation to the corresponding Wurster's Blue (WB)-type species that exhibits NIR absorptions up to λ=1200 nm. In the case of the N,N'-dimethyl derivative, cation radical 1 c(+.) is stable enough to be isolated as a salt and X-ray analysis indicated paraquinoid-type bond alternation in the WB core unit, whereas the bond lengths in the peripheral benzene rings are identical to those in the neutral donor. Upon electrochemical interconversion, the redox pairs of 1 a-c and 1 a-c(+.) exhibited an electrochromic response in the UV/Vis/NIR region, which was accompanied by a drastic change in the fluorescence spectrum because only neutral donors 1 a-c are highly emissive (Φ(F) : 0.7-0.8).

Direct synthesis of quinazolines through copper-catalyzed reaction of aniline-derived benzamidines.

A novel synthesis of 2-phenyl-4-[(triisopropylsilyl)methyl]quinazolines from monosubstituted arenes has been developed. Treatment of N-phenylbenzamidines with 5-nitro-1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one and K(2)CO(3) in the presence of a catalytic amount of CuBr in benzene gives 2-phenyl-4-[(triisopropylsilyl)methyl]quinazolines in moderate to good yields.