ISOPRENE OLIGOMER, POLYISOPRENE, PROCESSES FOR PRODUCING THESE MATERIALS, RUBBER COMPOSITION, AND PNEUMATIC TIRE
申请人:Miyagi Yukino
公开号:US20140171675A1
公开(公告)日:2014-06-19
The invention relates to an isoprene oligomer that contains a trans structural moiety and a cis structural moiety, which can be represented by the following formula (1), wherein at least 1 atom or group in the trans structural moiety is replaced by another atom or group. The invention also relates to a polyisoprene, which is biosynthesized using the isoprene oligomer and isopentenyl diphosphate. Further, this invention provides a rubber composition comprising the isoprene oligomer and/or the polyisoprene, and a pneumatic tire, including tire components (e.g., treads and sidewalls) formed from the rubber composition.
wherein n represents an integer from 1 to 10; m represents an integer from 1 to 30; and Y represents a hydroxy group, a formyl group, a carboxy group, an ester group, a carbonyl group, or a group represented by the following formula (2):
Diagnostic imaging methods using rhenium and technetium complexes
申请人:Bracco International B.V.
公开号:US05688487A1
公开(公告)日:1997-11-18
Novel methods, processes and metal complexes attached to a hypoxia-localizing moiety comprising a metal, preferably radionuclide of rhenium or technetium; a hypoxia-localizing moiety; and, a complexing ligand, wherein said ligand and said radionuclide combined have cell membrane permeabilities greater than that of sucrose, are disclosed.
作者:Nicholas L. Reed、Grace A. Lutovsky、Tehshik P. Yoon
DOI:10.1021/jacs.1c02747
日期:2021.4.28
and exceptionally mild photocatalytic oxidative heterofunctionalization reactions between bulky tri- and tetrasubstituted alkenes and a wide variety of nucleophilic partners. Moreover, we demonstrate that the broad scope of this transformation arises from photocatalytic alkeneactivation and thus complements existing transition-metal-catalyzed methods for oxidative heterofunctionalization. More broadly
Evolution of an oxidative dearomatization enabled total synthesis of vinigrol
作者:Qingliang Yang、Cristian Draghici、Jon T. Njardarson、Fang Li、Brandon R. Smith、Pradipta Das
DOI:10.1039/c3ob42191k
日期:——
synthetic strategy resulting in a totalsynthesis of vinigrol is presented. Oxidative dearomatization/intramolecular Diels–Alder cycloaddition has served as the successful cornerstone for all of the approaches. Extensive radical cyclization efforts to form the tetracyclic core resulted in interesting and surprising reaction outcomes, none of which could be advanced to vinigrol. These cyclization obstacles
One-Step Conversion of Alcohols into Nitriles with Simultaneous Two-Carbon Chain Elongation. (Cyanomethyl)trimethylphosphonium Iodide as a Reagent with a Dual Mode of Action
作者:Florencio Zaragoza
DOI:10.1021/jo025731r
日期:2002.7.1
Treatment of alcohols with an excess of (cyanomethyl)trimethylphosphonium iodide leads, after aqueous hydrolysis, to the clean formation of nitriles with two more carbon atoms than present in the original alcohol. Benzylic, allylic, and aliphatic alcohols without beta-branching (RCH(2)CH(2)OH) have been converted to nitriles with success. The required phosphonium iodide is simple to prepare and can