189028-94-2Relevant academic research and scientific papers
Controlling Chemoselectivity of Catalytic Hydroboration with Light
Bergamaschi, Enrico,Chen, Yi-Kai,Hohenadel, Melissa,Lunic, Danijela,McLean, Liam A.,Teskey, Christopher J.
, (2022/01/13)
The ability to selectively react one functional group in the presence of another underpins efficient reaction sequences. Despite many designer catalytic systems being reported for hydroboration reactions, which allow introduction of a functional handle fo
Synthesis method of chiral methyl 5-(4-fluorophenyl)-5-hydroxyvalerate
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, (2020/06/02)
The invention provides a synthesis method of chiral methyl 5-(4-fluorophenyl)-5-hydroxyvalerate. The method comprises the following steps: fluorobenzene and glutaric anhydride taken as raw materials undergo a Friedel-Crafts acylation reaction to synthesize 5-(4-fluorophenyl)-5-carbonylvaleric acid; the 5-(4-fluorophenyl)-5-carbonylvaleric acid undergoes a reduction reaction to synthesize 5-(4-fluorophenyl)-5-hydroxyvaleric acid; the 5-(4-fluorophenyl)-5-hydroxyvaleric acid undergoes a cyclization reaction to produce 6-(4-fluorophenyl)-tetrahydropyran-2-one; and the 6-(4-fluorophenyl)-tetrahydropyran-2-one undergoes an alcoholysis reaction to obtain the target compound, namely chiral methyl 5-(4-fluorophenyl)-5-hydroxyvalerate. The synthesis method avoids the problem that carbonyl and ester groups are easy to reduce at the same time, has the advantages of solution control of reaction conditions, high yield, mild reaction temperature, simplicity, easiness in implementation and low cost,and can realize industrial production.
Iridium-Catalyzed Asymmetric Hydrogenation of ?- A nd ?-Ketoacids for Enantioselective Synthesis of ?- A nd ?-Lactones
Hua, Yun-Yu,Bin, Huai-Yu,Wei, Tao,Cheng, Hou-An,Lin, Zu-Peng,Fu, Xing-Feng,Li, Yuan-Qiang,Xie, Jian-Hua,Yan, Pu-Cha,Zhou, Qi-Lin
, p. 818 - 822 (2020/02/15)
A highly efficient asymmetric hydrogenation of ?- A nd ?-ketoacids was developed by using a chiral spiro iridium catalyst (S)-1a, affording the optically active ?- A nd ?-hydroxy acids/lactones in high yields with excellent enantioselectivities (up to >99% ee) and turnover numbers (TON up to 100000). This protocol provides an efficient and practical method for enantioselective synthesis of Ezetimibe.
Study on the HPLC-based separation of some ezetimibe stereoisomers and the underlying stereorecognition process
Zhu, Bolin,Yao, Yaqi,Zhao, Yu,Sun, Tiemin,Li, Qing
, p. 642 - 651 (2018/02/12)
The enantioseparation of ezetimibe stereoisomers by high-performance liquid chromatography on different chiral stationary phases, ie, 3 polysaccharide-based chiral columns, was studied. It was observed that cellulose-based Chiralpak IC column exhibited the best resolving ability. After the optimization of mobile phase compositions in both normal and reversed phase modes, satisfactory separation could be obtained on Chiralpak IC column, especially in normal phase mode. The use of prohibited solvents as nonstandard mobile phase gave rise to better resolution than that of standard mobile phases (n-hexane/alcohol system). In addition, the presence of ethanol in nonstandard mobile phase has played an important role in enhancing chromatographic efficiency and resolution between ezetimibe stereoisomers. Various attempts were made to comprehensively compare the chiral recognition capabilities of immobilized versus coated polysaccharide-based chiral columns, amylose-based versus cellulose-based chiral stationary phases, reversed versus normal phase modes, and standard versus nonstandard mobile phases. Moreover, possible solute-mobile phase-stationary phase interactions were derived to explain how stationary and mobile phases affected the separation. Then the method validation with respect to selectivity, linearity, precision, accuracy, and robustness was carried out, which was demonstrated to be suitable and accurate for the quantitative determination of (RRS)-ezetimibe impurity in ezetimibe bulk drug.
METHOD OF PREPARING EZETIMIBE
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Paragraph 0041; 0042; 0043, (2015/02/18)
A method of preparing ezetimibe. The method includes converting a compound of formula (II) to a compound of formula (III) as shown below: in which R1-R5, A1, and A2 are defined in the specification.
NEW CCR2 RECEPTOR ANTAGONISTS AND USES THEREOF
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Page/Page column 46, (2012/01/14)
The present invention relates to novel antagonists for CCR2 (CC chemokine receptor 2) and their use for providing medicaments for treating conditions and diseases, especially pulmonary diseases like asthma and COPD.
PROCESS FOR ASYMMETRIC SYNTHESIS OF HYDROXY-ALKYL SUBSTITUTED AZETIDINONE DERIVATIVES OF INTERMEDIATES THEREOF
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Page/Page column 16-17, (2008/06/13)
Provided herein are processes for asymmetric synthesis of hydroxyalkyl-substituted azetidinone derivatives or intermediates thereof via stereoselective reduction of benzylic ketone using (-)-B-chlorodiisopinocampheylborane. Also provided herein are processes for preparing ezetimibe.
