216591-86-5Relevant academic research and scientific papers
Chiroptical Inversion of Europium(III) Complexes by Changing a Remote Stereogenic Center of a C2-Symmetric Bispyrrolidinoindoline Manifold
Taniguchi, Tomoaki,Tsubouchi, Akira,Imai, Yuki,Yuasa, Junpei,Oguri, Hiroki
, p. 15284 - 15296 (2018)
As an effort to integrate natural products chemistry and coordination chemistry, a diastereomeric pair of chiral alkaloidal manifolds composed of a bispyrrolidinoindoline (BPI) framework was designed and synthesized to generate luminescent EuIII complexes with switchable chiroptical properties. The C2-symmetric alkaloidal manifolds were linked with bis(benzimidazolyl)pyridine (BBIPy) as an achiral metal-binding component through substituents installed at the stereogenic 2/2′ positions of the BPI manifolds. The resulting diastereomeric pair of ligands, syn-L1 and anti-L2, allow pseudomirror symmetrical presentation of the metal-binding BBIPy units due to the stereogenic centers on the alkaloidal manifold. The ligand syn-L1 induces intramolecular coordination to form the 1:1 complex EuIII(syn-L1) composed of a single stranded metal helicate which exhibits a negative split Cotton effect. In contrast, the ligand anti-L2 led to a supramolecular assembly comprising the 2:2 complex EuIII2(anti-L2)2 consisting of a bimetallic double-stranded helicate which shows a positive split Cotton effect. Thus, the sp3 stereogenic centers in the BPI manifolds play pivotal roles in controlling both metal-ligand equilibria and chirality-switching of luminescent EuIII complexes. This approach, which exploits diastereomeric natural product-based manifolds, provides a relatively unexplored means for diversifying metal coordination modes and for controlling the chiroptical properties of the resultant luminescent lanthanoid complexes.
Microwave-assisted solid-phase synthesis of a 1,2-disubstituted benzimidazole library by using a phosphonium linker
Rios, Natalia,Chavarria, Cecilia,Gil, Carmen,Porcal, Williams
, p. 720 - 726 (2013/06/27)
An efficient and rapid microwave-assisted solid-phase method for the synthesis of 5-methyl-1,2-disubstituted benzimidazoles derivatives has been developed. The phosphonium linker, obtained by reaction between polymer-supported triphenylphosphine and 4-fluoro-3-nitrobenzyl iodide, underwent aromatic substitution with primary amines, followed by one-pot reaction with aldehydes in the presence of SnCl2·2H 2O, yielded the benzimidazole system under microwave irradiation. The final products were released from the resin with NaOH under microwave irradiation and were obtained in high purity and good overall yield.
Design and syntheses of a series of novel serotonin3 antagonists
Hori,Suzuki,Yamamoto,Nakajima,Ozaki,Ohtaka
, p. 1832 - 1841 (2007/10/02)
From a structural comparison study between serotonin and serotonin3 (5- HT3) antagonists using a two-dimensional grid template composed of regular hexagons, we deduced structural modification patterns from agonists to antagonists, an
