200948-88-5Relevant academic research and scientific papers
Development of Bifunctional Thiourea Organocatalysts Derived from a Chloramphenicol Base Scaffold and their Use in the Enantioselective Alcoholysis of meso Cyclic Anhydrides
Yan, Lin-Jie,Wang, Hai-Feng,Chen, Wen-Xue,Tao, Yuan,Jin, Kai-Jun,Chen, Fen-Er
, p. 2249 - 2253 (2016/07/19)
The synthesis of new chloramphenicol-base-derived thiourea organocatalysts, (1S,2R)-12 a–f and (1R,2R)-15 a–c, and their use in the enantioselective alcoholysis of meso-anhydrides are described. In particular, hemiesters afforded excellent enantioselectivities if low loadings of (1S,2R)-12 a–f were used. Almost no enantioselectivities were achieved with the use of (1R,2R)-15 a–c. This technique was used to synthesize (R)-(?)-baclofen.
Synthesis of cinchona alkaloid sulfonamide polymers as sustainable catalysts for the enantioselective desymmetrization of cyclic anhydrides
Takata, Shohei,Endo, Yuta,Shahid Ullah, Mohammad,Itsuno, Shinichi
, p. 72300 - 72305 (2016/08/09)
The Mizoroki-Heck polymerization of cinchona-based sulfonamide dimers and aromatic diiodides was investigated in the presence of a palladium catalyst, to obtain chiral polymers in high yields. An iodobenzenesulfonamide derivative of a cinchona alkaloid was also polymerized via self-polycondensation under the same reaction conditions. The catalytic activities of these chiral polymers were examined by using them as catalysts in the enantioselective desymmetrization of cyclic anhydrides.
Binding mode and structure-activity relationships around direct inhibitors of the Nrf2-Keap1 complex
Jnoff, Eric,Albrecht, Claudia,Barker, John J.,Barker, Oliver,Beaumont, Edward,Bromidge, Steven,Brookfield, Frederick,Brooks, Mark,Bubert, Christian,Ceska, Tom,Corden, Vincent,Dawson, Graham,Duclos, Stephanie,Fryatt, Tara,Genicot, Christophe,Jigorel, Emilie,Kwong, Jason,Maghames, Rosemary,Mushi, Innocent,Pike, Richard,Sands, Zara A.,Smith, Myron A.,Stimson, Christopher C.,Courade, Jean-Philippe
supporting information, p. 699 - 705 (2014/05/06)
An X-ray crystal structure of Kelch-like ECH-associated protein (Keap1) co-crystallised with (1S,2R)-2-[(1S)-1-[(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl) methyl]-1,2,3,4-tetrahydroisoquinolin-2-carbonyl]cyclohexane-1-carboxylic acid (compound (S,R,S)-1 a) was obtained. This X-ray crystal structure provides breakthrough experimental evidence for the true binding mode of the hit compound (S,R,S)-1 a, as the ligand orientation was found to differ from that of the initial docking model, which was available at the start of the project. Crystallographic elucidation of this binding mode helped to focus and drive the drug design process more effectively and efficiently. To dock or not to dock? Nrf2 has become an attractive neuroprotective target, as the Nrf2 pathway provides a natural cell defense mechanism against damage. Targeting its physiological negative modulator Keap1 with small molecules may allow Nrf2 to play its protective role. To this end, an X-ray structure of Keap1 co-crystallised with compound (S,R,S)-1 a was obtained, elucidating its binding mode, which in turn helped to drive the drug design process.
A family of novel bifunctional organocatalysts: Highly enantioselective alcoholysis of meso cyclic anhydrides and its application for synthesis of the key intermediate of P2X7 receptor antagonists
Yang, Hong-Jun,Xiong, Fang-Jun,Li, Jie,Chen, Fen-Er
, p. 553 - 558 (2013/07/27)
A family of novel squaramides/sulfamides based on 1,2-alkamine was developed as chiral bifunctional catalysts to promote the asymmetric alcoholysis of meso cyclic anhydrides. The hemiesters were obtained in high yield with up to 93% ee. The usefulness of this methodology was demonstrated in the asymmetric synthesis of the key intermediate of P2X7 receptor antagonists.
Inversion of enantioselectivity in quinine-mediated desymmetrization of glutaric meso-anhydrides
Ivsic, Trpimir,Hamersak, Zdenko
body text, p. 1095 - 1098 (2009/09/30)
An unexpected inversion of enantioselectivity, dependent on the degree of quinine loading, was observed during the desymmetrization of glutaric meso-anhydrides. Decrease in catalyst loading from 1.6 equiv to 0.1 equiv caused a clear inversion of stereoche
Macrocyclic design strategies for small, stable parallel β-sheet scaffolds
Freire, Felix,Gellman, Samuel H.
supporting information; experimental part, p. 7970 - 7972 (2009/12/02)
(Figure Presented) Pairs of short peptide strands can be induced to adopt an antiparallel β-sheet secondary structure in aqueous solution via a macrocyclic constraint, as illustrated by many natural and designedpeptides. We show that an analogous strategy is successful for creation of small units of parallel β-sheet secondary structure in aqueous solution. Cyclization in this case requires nonpeptide segments for N-to -N and C-to-C interstrand linkage. Surprisingly, we find that only one of these segments needs to be preorganized.
Diacid linkers that promote parallel β-sheet secondary structure in water
Freire, Felix,Fisk, John D.,Peoples, Aaron J.,Ivancic, Monika,Guzei, Ilia A.,Gellman, Samuel H.
supporting information; experimental part, p. 7839 - 7841 (2009/02/01)
We report the development of diacid units that promote formation of a two-stranded parallel β-sheet secondary structure between peptide segments attached via their N-termini. These linker units are formed by attaching glycine to one carboxyl group of cis-1,2-cyclohexanedicarboxylic acid (CHDA). Parallel sheet formation in water is observed when L-residue strands are attached to the CHDA-Gly unit with either of the two absolute configurations. Copyright
An alkaloid-mediated desymmetrization of meso-anhydrides via a nucleophilic ring opening with benzyl alcohol and its application in the synthesis of highly enantiomerically enriched β-amino acids
Zhang, Mingbao,Zhu, Lei,Ma, Xin
, p. 3455 - 3468 (2007/10/03)
The cinchona alkaloid-mediated opening of prochiral cyclic anhydrides in the presence of benzyl alcohol leading to optically active hemiesters is described. Structurally diverse anhydrides are converted into their corresponding benzyl monoesters with either enantiomer being obtained with up to 99 percent e.e. by using quinine or quinidine as the directing additive. A simple aqueous work-up protocol permits the isolation of the products in analytically pure form and the recovery of the alkaloids almost quantitatively. These hemiesters can be converted to N-protected β-amino esters by means of Curtius degradation of the corresponding acyl azides. Subsequent cleavage of both protecting groups by a single reaction step leads to the free β-amino acids in excellent yields. The efficiency of this procedure is demonstrated by the short asymmetric synthesis of the fungicide cis-pentacin delivering the amino acid with >99.7 percent enantiomeric excess.
