Chiral Phosphinyl Enamines and Their Asymmetric Reduction through Group-Assisted Purification Chemistry Leading to Enantiopure β-Amino Esters/Amides

Synlett ◽  
2017 ◽  
Vol 28 (18) ◽  
pp. 2483-2488 ◽  
Author(s):  
Bo Jiang ◽  
Guigen Li ◽  
Shuo Qiao ◽  
Jianbin Wu ◽  
Junming Mo ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Efficient Method ◽  
Asymmetric Reduction ◽  
Sodium Cyanoborohydride ◽  
Amino Esters

A series of new chiral N-phosphinyl β-enamino esters and amides were successfully prepared with excellent Z-stereoselectivity (Z/E > 99:1 in nearly all cases). Group-assisted purification chemistry proved to be an efficient method for the asymmetric reduction of the resulting β-enamino esters/amides to give enantiopure β-amino esters/amides. The asymmetric reduction can be controlled efficiently by using a combination of sodium cyanoborohydride and acetic acid.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

Synthesis of S-Licarbazepine by Asymmetric Reduction of Oxcarbazepine in Organic Solvent/Phosphate Buffer Biphasic System

2018 ◽  
Vol 921 ◽  
pp. 54-59
Author(s):  
Zhi Hin Ou ◽  
Jia Hui Xu
Keyword(s):  
Organic Solvent ◽  
Bacillus Anthracis ◽  
Efficient Method ◽  
Substrate Concentration ◽  
Phosphate Buffer ◽  
Dibutyl Phthalate ◽  
Cell Concentration ◽  
Asymmetric Reduction ◽  
Volume Ratio ◽  
Biphasic System

S-licarbazepine was synthesized by asymmetric reduction of oxcarbazepine in organic solvent/phosphate buffer biphasic system with Bacillus anthracis CGMCC No.12337 as catalyst. Effects of many factors on reduction were studied. Dibutyl phthalate/phosphate buffer was selected as the optimal biphasic system for reduction. The optimum reduction conditions are as follows: volume ratio of dibutyl phthalate and phosphate buffer 1:1, 30 g/L iospropanol as co-substrate, phosphate buffer pH 5, substrate concentration 7.92 mmol/L, cell concentration 30 g/L, 32°C，180 rpm. The conversion and enantiometric excess of S-licarbazepine reached 97.32% and 99.80%. An efficient method for synthesis of S-licarbazepine was provided.

scholarly journals A Facile and Efficient Method for Catalytic Acetylation of Alcohols with Acetic Acid

2010 ◽  
Vol 31 (12) ◽  
pp. 3870-3871 ◽  
Author(s):  
Anindita Dewan ◽  
Utpal Bora ◽  
Dilip Kumar Kakati
Keyword(s):  
Acetic Acid ◽  
Efficient Method

Efficient method for the asymmetric reduction of α- and β-ketophosphonates

Tetrahedron ◽  
2007 ◽  
Vol 63 (29) ◽  
pp. 6720-6731 ◽  
Author(s):  
V.V. Nesterov ◽  
O.I. Kolodiazhnyi
Keyword(s):  
Efficient Method ◽  
Asymmetric Reduction

scholarly journals A novel and efficient method to prepare 2-aryltetrahydrofuran-2-ylphosphonic acids

2010 ◽  
Vol 6 ◽  
Author(s):  
Vsevolod V Komissarov ◽  
Anatoly M Kritzyn ◽  
Jouko J Vepsäläinen
Keyword(s):  
Acetic Acid ◽  
Efficient Method ◽  
Phosphonic Acid ◽  
Acid Group ◽  
Phosphorus Trichloride ◽  
One Pot ◽  
End Products ◽  
Phosphonic Acid Group ◽  
Acidic Conditions ◽  
Anchimeric Assistance

A novel one-pot method was developed for the synthesis of the title compounds starting from 4-chloro-1-aryl-1-butanones 1, phosphorus trichloride and acetic acid. The end products 2 were obtained in 20–94% yield. The cyclization step under acidic conditions probably occurs as a result of anchimeric assistance of the phosphonic acid group.

A Mild and Efficient Method for Racemization of α-Amino Esters.

ChemInform ◽  
2004 ◽  
Vol 35 (17) ◽  
Author(s):  
Uma Ramachandran ◽  
Sudhanshu Kumar ◽  
H. P. S. Chawla
Keyword(s):  
Efficient Method ◽  
Amino Esters

ChemInform Abstract: A Highly Efficient Method for the α,β-Dehydrogenation of α-Amino Esters and α-Amino-β-diesters.

ChemInform ◽  
2010 ◽  
Vol 42 (4) ◽  
pp. no-no
Author(s):  
Marco Pallavicini ◽  
Cristiano Bolchi ◽  
Laura Fumagalli ◽  
Oreste Piccolo ◽  
Ermanno Valoti
Keyword(s):  
Efficient Method ◽  
Amino Esters ◽  
Highly Efficient

scholarly journals Multiphase extraction of ephedrine from Pinellia ternata using bionic liquid-modified polymer

2019 ◽  
Vol 21 (4) ◽  
pp. 13-19
Author(s):  
Luwei Fang ◽  
Minglei Tian ◽  
Liangwen Lin ◽  
Kyung Ho Row
Keyword(s):  
Ionic Liquid ◽  
Acetic Acid ◽  
Efficient Method ◽  
Adsorption Efficiency ◽  
Pinellia Ternata ◽  
Modified Polymer ◽  
Multiphase Extraction

Abstract Multiphase extraction (MPE) was applied as a developed, convenient and efficient method in separation of ephedrine from Pinellia ternata. Firstly, in order to increase the adsorption efficiency, bionic liquid-modified polymer was created. Comparing the effects of all sorbents under variables conditions, the highest amount of 5.8 mg/g can be adsorbed on dual imidazole ionic liquid modified polymer (Im-Im-Poly) in methanol/water (70:30, v/v) solution at 25°C within 30.0 min. Then the Im-Im-Poly was applied in MPE, after 7 times repetition of extraction, around 1.0 mg/g of ephedrine from Pinellia ternata was detected. After washing by water, ethanol and methanol, and elution by methanol/acetic acid (99.0:1.0, v/v), ephedrine was successfully separated.

Sign in / Sign up

Export Citation Format

Share Document