14258-40-3Relevant articles and documents
A Family of Amphiphilic Cyclodextrin Liquid Crystals Governed by Dipole–Dipole Interactions
Champagne, Pier-Luc,Ester, David,Ward, Sandra,Williams, Vance E.,Ling, Chang-Chun
, p. 423 - 432 (2017)
A novel family of amphiphilic cyclodextrin(CD)-based liquid crystals that bear O-acetylated oligoethylene glycol chains at the secondary face is reported. Unlike most of the previously reported liquid crystals (LC) based on chemically modified CDs, which depend on H-bonding as the primary intermolecular forces, the present CD derivatives self-assemble into highly ordered smectic liquid crystal phases via the weaker dipole–dipole intermolecular interactions. The obtained materials are found to display much improved properties such as improved thermostability, reduced clearing temperatures, and better fluidity. The present work opens up new possibilities to design CD-based LC materials.
Synthesis Toward and Stereochemical Assignment of Clathsterol: Exploring Diverse Strategies to Polyoxygenated Sterols
Zhou, Tao,Feng, Feng,Shi, Yong,Tian, Wei-Sheng
, p. 2308 - 2311 (2016)
Herein we describe a synthesis of the trisulfate derivative of clathsterol (1), a marine sterol endowed with impressive structural features and moderate inhibitory activity against HIV-1 reverse transcriptase. By synthesizing two possible isomers of the side chain, the stereochemistry of 1 is assigned. In creating chiral side chains from steroidal lactone, our strategies, including an addition/reduction procedure to give C22R-OH, an epoxide-opening reaction, and a [3.3]-rearrangement to induce the generation of C24S-Et and C24R-Et respectively, are highly flexible and complementary to each other.
Triazine-Based Cationic Leaving Group: Synergistic Driving Forces for Rapid Formation of Carbocation Species
Fujita, Hikaru,Kakuyama, Satoshi,Fukuyoshi, Shuichi,Hayakawa, Naoko,Oda, Akifumi,Kunishima, Munetaka
supporting information, p. 4568 - 4580 (2018/04/26)
A new triazine-based cationic leaving group has been developed for the acid-catalyzed alkylation of O- and C-nucleophiles. There are two synergistic driving forces, namely, stable C=O bond formation and charge-charge repulsive effects, involved in the rapid generation of the carbocation species in the presence of trifluoromethanesulfonic acid (~200 mol %). Considerable rate acceleration of benzylation, allylation, and p-nitrobenzylation was observed as compared to the reactions with less than 100 mol % of the acid catalyst. The triazine-based leaving group showed superior p-nitrobenzylation yield and stability in comparison to common leaving groups, trichloroacetimidate and bromide. A plausible reaction mechanism (the cationic leaving group pathway) was proposed on the basis of mechanistic and kinetic studies, NMR experiments, and calculations.