71031-04-4Relevant academic research and scientific papers
Engineering a homochiral metal-organic framework based on an amino acid for enantioselective separation
Tang, Haitong,Yang, Keke,Wang, Kun-Yu,Meng, Qi,Wu, Fan,Fang, Yu,Wu, Xiang,Li, Yougui,Zhang, WenCheng,Luo, Yunfei,Zhu, Chengfeng,Zhou, Hong-Cai
, p. 9016 - 9019 (2020/08/17)
A chiral metal-organic framework possessing an open amphiphilic channel is constructed from a dicarboxylate ligand derived from an amino acid and is shown to be an efficient and recyclable chiral solid adsorbent, which is capable of separating racemic secondary alcohols, epoxides, and ibuprofen with very high enantioselectivity.
Modulators of cell adhesion, methods and compositions therefor
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Paragraph 0220; 0221, (2019/04/18)
Compounds with activity as modulators of cell adhesion are disclosed. The compounds are derivatives of piperidin-4-amine. In some embodiments, a compound can be linked to a targeting agent, a pharmaceutically active substance and/or a support material. Methods for enhancing or inhibiting classical cadherin-mediated functions are also disclosed. The compounds can be used for the treatment or prevention of a variety of diseases including cancer. Compositions and devices, including skin patches comprising a compound are also disclosed. In addition, methods of synthesis of the compounds are provided.
Chiral Bifunctional Metalloporphyrin Catalysts for Kinetic Resolution of Epoxides with Carbon Dioxide
Maeda, Chihiro,Mitsuzane, Mayato,Ema, Tadashi
supporting information, p. 1853 - 1856 (2019/03/11)
Chiral binaphthyl-strapped Zn(II) porphyrins with triazolium halide units were synthesized as bifunctional catalysts for kinetic resolution of epoxides with CO2. Several catalysts were screened by changing the linker length and nucleophilic counteranions, and the optimized catalyst accelerated the enantioselective reaction at ambient temperature to produce optically active cyclic carbonates and epoxides.
Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
supporting information, p. 3990 - 4001 (2017/11/22)
New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
Chiral Macrocyclic Organocatalysts for Kinetic Resolution of Disubstituted Epoxides with Carbon Dioxide
Ema, Tadashi,Yokoyama, Maki,Watanabe, Sagiri,Sasaki, Sota,Ota, Hiromi,Takaishi, Kazuto
supporting information, p. 4070 - 4073 (2017/08/15)
Among chiral macrocycles 1 synthesized, 1m with the 3,5-bis(trifluoromethyl)phenylethynyl group was the best organocatalyst for the enantioselective synthesis of cyclic carbonates from disubstituted or monosubstituted epoxides and CO2. The X-ray crystal structure of 1m revealed a well-defined chiral cavity with multiple hydrogen-bonding sites that is suitable for the enantioselective activation of epoxides. A catalytic cycle proposed was supported by DFT calculations.
Synthesis, radiolabeling and in vivo evaluation of [11C](R)-1- [4-[2-(4-methoxyphenyl)phenyl]piperazin-1-yl]-3-(2-pyrazinyloxy)-2-propanol, a potential PET radioligand for the 5-HT7receptor
Hansen, Hanne D.,Lacivita, Enza,Di Pilato, Pantaleo,Herth, Matthias M.,Lehel, Szabolcs,Ettrup, Anders,Andersen, Valdemar L.,Dyssegaard, Agnete,De Giorgio, Paola,Perrone, Roberto,Berardi, Francesco,Colabufo, Nicola Antonio,Niso, Mauro,Knudsen, Gitte M.,Leopoldo, Marcello
, p. 152 - 163 (2014/05/06)
In the search for a novel serotonin 7 (5-HT7) receptor PET radioligand we synthesized and evaluated a new series of biphenylpiperazine derivatives in vitro. Among the studied compounds, (R)-1-[4-[2-(4-methoxyphenyl) phenyl]piperazin-1-yl]-3-(2-pyrazinyloxy)-2-propanol ((R)-16), showed the best combination of affinity, selectivity, and lipophilicity, and was thus chosen for carbon-11 labelling and evaluation in pigs. After intravenous injection, [11C](R)-16 entered the pig brain and displayed reversible tracer kinetics. Pretreatment with the 5-HT7receptor selective antagonist SB-269970 (1) resulted in limited decrease in the binding of [11C](R)-16, suggesting that this radioligand is not optimal for imaging the brain 5-HT7receptor in vivo but it may serve as a lead compound for the design of novel 5-HT7receptor PET radioligands.
Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(iii)-salen complexes: A practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: Computational rationale for enantioselectivity
Roy, Tamal,Barik, Sunirmal,Kumar, Manish,Kureshy, Rukhsana I.,Ganguly, Bishwajit,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
, p. 3899 - 3908 (2015/02/19)
A series of chiral polymeric Co(iii)-salen complexes based on a number of achiral and chiral linkers were synthesized and their catalytic performances were assessed in the asymmetric hydrolytic kinetic resolution of terminal epoxides. The effects of the linker were judiciously studied and it was found that in the case of the chiral BINOL-based polymeric salen complex 1, there was an enrichment in catalyst reactivity and enantioselectivity of the unreacted epoxide, particularly in the case of short as well as long chain aliphatic epoxides. Good isolated yields of the unreacted epoxide (up to 46% compared to 50% theoretical yield) along with high enantioselectivity (up to 99%) were obtained in most cases using catalyst 1. Further studies showed that catalyst 1 could retain its catalytic activity for six cycles under the present reaction conditions without any significant loss in activity or enantioselectivity. To show the practical applicability of the above synthesized catalyst we have synthesised some potent chiral β-blockers in moderate yield and high enantioselectivity using complex 1. The DFT (M06-L/6-31+G??//ONIOM(B3LYP/6-31G?:STO-3G)) calculations revealed that the chiral BINOL linker influences the enantioselectivity achieved with Co(iii)-salen complexes. Further, the transition state calculations show that the R-BINOL linker with the (S,S)-Co(iii)-salen complex is energetically preferred over the corresponding S-BINOL linker with the (S,S)-Co(iii)-salen complex for the HKR of 1,2-epoxyhexane. The role of non-covalent C-H?π interactions and steric effects has been discussed to control the HKR reaction of 1,2-epoxyhexane.
Enantioselective α-hydroxylation of β-keto esters catalyzed by chiral S-timolol derivatives
Cai, Yuanchun,Lian, Mingming,Li, Zhi,Meng, Qingwei
experimental part, p. 7973 - 7977 (2012/09/21)
A screen of aryloxy aminopropanol organocatalysts derived from the β-blocker inhibitor S-timolol determined the most active catalyst of asymmetric α-hydroxylation of β-keto esters. (R)-1-(tert-butylamino)- 3-(3,4,5-trimethoxyphenoxy) propan-2-ol (3k) was the most effective derivative, enantioselectively catalyzing α-hydroxylation of β-keto esters using tert-butyl hydroperoxide as the oxidant in hexane to afford the corresponding products in excellent yield and with good enantioselectivity (up to 96% yield, 88% ee).
Chiral nanoporous metal-metallosalen frameworks for hydrolytic kinetic resolution of epoxides
Zhu, Chengfeng,Yuan, Guozan,Chen, Xu,Yang, Zhiwei,Cui, Yong
supporting information; experimental part, p. 8058 - 8061 (2012/07/14)
Chiral nanoporous metal-organic frameworks are constructed by using dicarboxyl-functionalized chiral Ni(salen) and Co(salen) ligands. The Co(salen)-based framework is shown to be an efficient and recyclable heterogeneous catalyst for hydrolytic kinetic resolution (HKR) of racemic epoxides with up to 99.5% ee. The MOF structure brings Co(salen) units into a highly dense arrangement and close proximity that enhances bimetallic cooperative interactions, leading to improved catalytic activity and enantioselectivity in HKR compared with its homogeneous analogues, especially at low catalyst/substrate ratios.
Directed evolution of an enantioselective epoxide hydrolase: Uncovering the source of enantioselectivity at each evolutionary stage
Reetz, Manfred T.,Bocola, Marco,Wang, Li-Wen,Sanchis, Joaquin,Cronin, Annette,et al.
supporting information; experimental part, p. 7334 - 7343 (2009/10/17)
Directed evolution of enzymes as enantioselective catalysts in organic chemistry is an alternative to traditional asymmetric catalysis using chiral transition-metal complexes or organocatalysts, the different approaches often being complementary. Moreover, directed evolution studies allow us to learn more about how enzymes perform mechanistically. The present study concerns a previously evolved highly enantioselective mutant of the epoxide hydrolase from Aspergillus niger in the hydrolytic kinetic resolution of racemic glycidyl phenyl ether. Kinetic data, molecular dynamics calculations, molecular modeling, inhibition experiments, and X-raystructural work for the wild-type (WT) enzyme and the best mutant revea l the basis of the large increase in enantioselectivity (E = 4.6 versus E = 115). The overall structures of the WT and the mutant are essentially identical, but dramatic differences are observed in the active site asrevealed by the X-ray structures. All of the experimental and computati onal results support a model in which productive positioning of the preferred (S)-glycidyl phenyl ether, but not the (R)-enantiomer, forms the basis of enhanced enantioselectivity. Predictions regarding substrate scope and enantioselectivity of the best mutant are shown to be possible.
