scholarly journals Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates

2019 ◽  
Vol 10 (45) ◽  
pp. 10510-10515 ◽  
Author(s):  
Haile Qiu ◽  
Xiaofeng Chen ◽  
Junliang Zhang

A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fariba Peytam ◽  
Ghazaleh Takalloobanafshi ◽  
Toktam Saadattalab ◽  
Maryam Norouzbahari ◽  
Zahra Emamgholipour ◽  
...  

AbstractIn an attempt to find novel, potent α-glucosidase inhibitors, a library of poly-substituted 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines 3a–ag have been synthesized through heating a mixture of 2-aminobenzimidazoles 1 and α-azidochalcone 2 under the mild conditions. This efficient, facile protocol has been resulted into the desirable compounds with a wide substrate scope in good to excellent yields. Afterwards, their inhibitory activities against yeast α-glucosidase enzyme were investigated. Showing IC50 values ranging from 16.4 ± 0.36 µM to 297.0 ± 1.2 µM confirmed their excellent potency to inhibit α-glucosidase which encouraged us to perform further studies on α-glucosidase enzymes obtained from rat as a mammal source. Among various synthesized 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines, compound 3k exhibited the highest potency against both Saccharomyces cerevisiae α-glucosidase (IC50 = 16.4 ± 0.36 μM) and rat small intestine α-glucosidase (IC50 = 45.0 ± 8.2 μM). Moreover, the role of amine moiety on the observed activity was studied through substituting with chlorine and hydrogen resulted into a considerable deterioration on the inhibitory activity. Kinetic study and molecular docking study have confirmed the in-vitro results.


ChemInform ◽  
2010 ◽  
Vol 25 (40) ◽  
pp. no-no
Author(s):  
D. H. KIM ◽  
Y. M. KIM ◽  
Z.-H. LI ◽  
K. B. KIM ◽  
S. Y. CHOI

2012 ◽  
Vol 22 (17) ◽  
pp. 5363-5366 ◽  
Author(s):  
Yan Wang ◽  
Guri L.V. Damu ◽  
Jing-Song Lv ◽  
Rong-Xia Geng ◽  
Da-Cheng Yang ◽  
...  

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 53 ◽  
Author(s):  
Carlos Luna ◽  
Diego Luna ◽  
Felipa Bautista ◽  
Juan Calero ◽  
Antonio Romero ◽  
...  

In this study, the evaluation of the catalytic behavior of several wild bacterial strains in the 1,3-selective ethanolysis of triglycerides with ethanol to produce a new type of biodiesel (Ecodiesel) that integrates glycerol as monoacylglycerols was carried out. The Ecodiesel production not only avoids the elimination of glycerol, which is largely generated as a by-product in the biodiesel industry, but also results in an increase in the biofuel yield. The wild microbial strain samples were obtained from several lipophilic organisms. In addition to evaluate the enzymatic extracts, the minimum grade of purification of the strains, necessary to obtain similar results to those attained with commercial lipases was studied. This purification treatment included a dialysis followed by a lyophilization process. Such extracts were directly used as biocatalysts in the transesterification reaction of sunflower oil with ethanol, attaining much better results (yield close to 100%) than those obtained with strains which were not submitted to the purification process (yields lower than 10%). Furthermore, the results here obtained are similar to those obtained with commercial lipases but were achieved under mild conditions and lower reaction time (2 h). In addition, the stability of the enzymatic extracts was corroborated by subsequent reactions, showing no loss of activity. Thus, this study brings to light that enzymatic extracts obtained by a very simple purification process can be economically competitive with the conventional biodiesel production methods.


ACS Catalysis ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 6991-6998 ◽  
Author(s):  
Xiaoyang Pan ◽  
Xiang Gao ◽  
Xuxing Chen ◽  
Ho Nyung Lee ◽  
Yun Liu ◽  
...  

2020 ◽  
Vol 11 (12) ◽  
pp. 3326-3331 ◽  
Author(s):  
Yanhua Xu ◽  
Samya Sen ◽  
Qiong Wu ◽  
Xujia Zhong ◽  
Randy H. Ewoldt ◽  
...  

A new type of base-triggered self-amplifying degradable polyurethane is reported that degrades under mild conditions, with the release of increasing amounts of amine product leading to self-amplified degradation.


2011 ◽  
Vol 225-226 ◽  
pp. 1279-1283
Author(s):  
Guo Cheng Li

In this paper, a solution for engineering equilibrium mathematics modeling (EEMM) is considered. To obtain a solution of EEMM, we present a new type alternating direction solution method, and then its convergence is also shown under mild conditions. The results obtained in this paper can be taken as an extension of the existing method for EEMM.


2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Hugo Santalla ◽  
Uxía Gómez-Bouzó ◽  
Irene Sánchez-Sanz ◽  
Yagamare Fall

A new vitamin D analogue with a trans-fused decalin as the CD-ring system and containing a sulphur atom in the side chain has been synthesized in our research group. The obtention of this analogue is based on a recently discovered transformation of hydrindane cores into decalins through a dyotropic ring expansion in very mild conditions.


2020 ◽  
Vol 49 (29) ◽  
pp. 10104-10113 ◽  
Author(s):  
Dan Zhao ◽  
Yali Xue ◽  
Ruijuan Zhang ◽  
Yanping Fan ◽  
Baozhong Liu ◽  
...  

This work provides a novel host lattice template CsNa2REE2(BO3)(PO4)2 (REE = Y, Gd, Lu) for Eu3+ luminescence, with a linear arrangement of REE3+ ions that restricts the occurrence of concentration quenching even for fully concentrated Eu3+.


1994 ◽  
Vol 49 (1) ◽  
pp. 76-88 ◽  
Author(s):  
Dieter Sellmann ◽  
Helge Friedrich ◽  
Falk Knoch ◽  
Matthias Moll

Abstract Single pot reactions of FeCl2∙4H2O with the tetradentate thioether-thiol 'S4-H2' = 1,2-bis(2-mercaptophenylthio)ethane, phosphines such as PEt3, PPr3 or PBu3, and a ca. 40-fold excess of N2H4∙H2O yield, in the presence of air, diazene complexes of the general formula [µ-N2H2{Fe(PR3)('S4')}2]. In contrast to previous syntheses of diazene complexes, the yields can excel 80%, and the syntheses can be carried out on a 10 g scale. [µ-N2H2{Fe(PPr3)('S4')}2], 1 and [µ-N2H2{Fe(PEt3)('buS4')}2], 2 were characterized by X-ray structure analysis. 2 contains 'buS4'2−= 1,2-bis(3,5-ditertiarybutyl-2-mercaptophenylthio)-ethane(2-), which is the tertiary-butyl derivative of 'S4'2−. 1 and 2 contain trans-HN=NH which bridges enantiomeric [Fe(PPr3)('S4')] or [Fe(PEt3)('buS4')] fragments. HN=NH is stabilized by 4c - 6 e− - π bonds, strong tricentric N − H∙∙∙(S)2 bridges, and steric shielding. NMR studies show that centrosymmetric 1 isomerizes in solution at temperatures around 0 °C in order to give a diastereomerie diazene complex which is also centrosymmetric. The diastereomerism is traced back to bridging the chiral [Fe(PPr3)('S4')] fragments by trans-HN=NH in a different way. The two different bridging modes are verified by X-ray structure analyses of analogous ruthenium complexes. Because this new type of diastereomerism is basically caused by a different position only of the N − H∙∙∙(S)2 bridges, it is termed hydrogen bridge diastereomerism. A mechanism for the isomerization is suggested. 1 exhibits three anodic waves in the cyclovoltammogram. The second wave indicates formation of the dication [1]2+, which is a redox isomer of the diprotonated (and as yet hypothetical) dinitrogen complex [µ-N2{Fe(PPr3)('S4')}2]. The significance of [1]2+ and of its Lewis basic thiolate donors with respect to electrochemical reduction of molecular dinitrogen under mild conditions is discussed.


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