130232-97-2Relevant academic research and scientific papers
Enantioselective Resolution Copolymerization of Racemic Epoxides and Anhydrides: Efficient Approach for Stereoregular Polyesters and Chiral Epoxides
Li, Jie,Ren, Bai-Hao,Wan, Zhao-Qian,Chen, Shi-Yu,Liu, Ye,Ren, Wei-Min,Lu, Xiao-Bing
supporting information, p. 8937 - 8942 (2019/06/11)
Herein we report an efficient strategy for preparing isotactic polyesters and chiral epoxides via enantioselective resolution copolymerization of racemic terminal epoxides with anhydrides, mediated by enantiopure bimetallic complexes in conjunction with a nucleophilic cocatalyst. The chirality of both the axial linker and the diamine backbones of the ligand are responsible for the chiral induction of this kinetic resolution copolymerization process. The catalyst systems exhibit exceptional levels of enantioselectivity with a kinetic resolution coefficient exceeding 300 for various racemic epoxides, affording highly isotactic copolymers (selectivity factors of more than 300) with a completely alternating structure and low polydispersity index. Most of the produced isotactic polyesters are typical semicrystalline materials with melting temperatures in the range from 77 to 160 °C.
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.).
Development of a scalable synthesis of (S)-3-fluoromethyl-γ- butyrolactone, building block for Carmegliptin's Lactam moiety
Adam, Jean-Michel,Foricher, Joseph,Hanlon, Steven,Lohri, Bruno,Moine, Gerard,Schmid, Rudolf,Wirz, Beat,Zutter, Ulrich,Stahr, Helmut,Weber, Martin
experimental part, p. 515 - 526 (2011/12/05)
Several new routes are reported for the synthesis of (S)-3-fluoromethyl- γ-butyrolactone. An asymmetric hydrogenation-based synthesis was chosen as the enabling route to produce the lactone on a 10-kg scale. A superior stereoselective route starting from (S)-tert-butyl glycidyl ether which afforded the desired lactone in three steps with ~50% overall yield was finally selected for further development and production.
PROCESS FOR THE PREPARATION OF (S)-4-FLUOROMETHYL-DIHYDRO-FURAN-2-ONE
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Page/Page column 8, (2008/12/04)
The present invention relates to a process of the preparation of (S)-4-fluoromethyl-dihydro-furan-2-one of the formula by employing a dialkylmalonate of the formula wherein R1b is lower alkyl, and the use of this process for the manufacture of DPP-IV inhibitors that are useful for the treatment and/or prophylaxis of diseases such as diabetes.
A new dinuclear chiral salen complexes for asymmetric ring opening and closing reactions: Synthesis of valuable chiral intermediates
Thakur, Santosh Singh,Chen, Shu-Wei,Li, Wenji,Shin, Chang-Kyo,Kim, Seong-Jin,Koo, Yoon-Mo,Kim, Geon-Joong
, p. 1862 - 1872 (2007/10/03)
A new dinuclear chiral Co(salen) complexes bearing group 13 metals have been synthesized and characterized. The easily prepared complexes exhibited very high catalytic reactivity and enantioselectivity for the asymmetric ring opening of epoxides with H2O, chloride ions and carboxylic acids and consequently provide enantiomerically enriched terminal epoxides (>99% ee). It also catalyzes the asymmetric cyclization of ring opened product, to prepare optically pure terminal epoxides in one step. The homogeneous dinuclear chiral Co(salen) have been covalently immobilized on MCM-41. The potential benefits of heterogenization include facilitation of catalyst separation and recyclability requiring very simple techniques. The system described is very efficient.
Angiogenesis inhibitor TX-1898: Syntheses of the enantiomers of sterically diverse haloacetylcarbamoyl-2-nitroimidazole hypoxic cell radiosensitizers
Jin, Cheng-Zhe,Nagasawa, Hideko,Shimamura, Mariko,Uto, Yoshihiro,Inayama, Seiichi,Takeuchi, Yoshio,Kirk, Kenneth L.,Hori, Hitoshi
, p. 4917 - 4927 (2007/10/03)
(R)- and (S)-Epichlorohydrins were used to prepare the enantiomers of sterically diverse haloacetylcarbamoyl-2-nitroimidazoles that function as hypoxic cell radiosensitizers. The synthetic design allowed for introduction of a side chain of varying bulk th
The efficient resolution of protected diols and hydroxy aldehydes by lipases: Steric auxilliary approach and synthetic applications
Kim,Lim,Choi,Whang,Ku,Choi
, p. 71 - 76 (2007/10/03)
1,n-Diols (n = 2-5) and 2-hydroxy aldehydes protected with a steric auxilliary are transformed by Pseudomonas lipases with high enantioselectivity, thus allowing the efficient resolution of these molecules and the synthesis of related derivatives with high optical purity.
