scholarly journals Carbapenems as water soluble organocatalysts

2018 ◽  
Vol 3 ◽  
pp. 107 ◽  
Author(s):  
Thomas L. Williams ◽  
Alexander R. Nödling ◽  
Yu-Hsuan Tsai ◽  
Louis Y. P. Luk
Keyword(s):  
Secondary Amine ◽  
Future Development ◽  
Michael Addition ◽  
Model Reaction ◽  
Water Soluble ◽  
Chiral Hplc ◽  
Chemical Transformations ◽  
H Nmr ◽  
Aqueous Environments ◽  
The Michael Addition

Background: Identification of organocatalysts functioning in aqueous environments will provide methods for more sustainable chemical transformations and allow tandem reactions with biocatalysts, like enzymes. Here we examine three water-soluble carbapenem antibiotics (meropenem, doripenem, and ertapenem) as secondary amine organocatalysts in aqueous environments. Methods: The Michael addition of nitromethane to cinnamaldehyde was used as the model reaction. The reactions were monitored by 1H NMR, and the enantioselectivity was determined by chiral HPLC.   Results: The effects of buffer components, pH, organic co-solvents and anchoring into a protein scaffold were investigated. Moderate yields of the Michael addition were obtained in buffer alone. The use of methanol as a co-solvent in a ratio of 1:1 increases the yield by 50%. Anchoring of the catalysts into a protein backbone reverses the enatioselectivity of the reaction. Conclusions: Despite only moderate yields and enantioselectivities being obtained, this study lays the foundations for future development of efficient organocatalysis in aqueous environments.

On the Stereoselectivity of the (-)-Dimenthyl Malonate Addition to α,β-Unsaturated Ketones

1996 ◽  
Vol 61 (12) ◽  
pp. 1805-1814 ◽  
Author(s):  
Ľubomír Šebo ◽  
Juraj Alföldi ◽  
Grety Rihs ◽  
Štefan Toma
Keyword(s):  
Michael Addition ◽  
Pure State ◽  
Nmr Spectra ◽  
Reaction Products ◽  
X Ray ◽  
Unsaturated Ketones ◽  
H Nmr ◽  
The Michael Addition

The Michael addition of (-)-dimenthyl malonate to eight α,β-unsaturated ketones has been studied. The ratio of diastereomers was calculated on the basis of the 1H NMR spectra of the crude reaction products. The diastereomer excess varied from 10 to 50%, depending on the structure of the starting enone. The pure diastereomer produced by addition of (-)-dimenthyl malonate to 2-benzylidene-1,4-indandione was isolated by repeated crystallization. X-ray analysis has shown that the isomer is (-)-dimenthyl (R)-2-[1-(1,3-dioxoindan-2-yl)-1-phenylmethyl]malonate (5a). The predominating diastereomers of (-)-dimenthyl(3-ferrocenyl-3-oxophenylpropyl)malonate (1a) and (-)-dimenthyl-2-(1-(1,3-dioxo[3]ferrocenophan-2-yl)-1-phenyl malonate (6a) were also isolated in pure state by careful crystallization.

Synthesis, Characterization, and Drug Encapsulation of Hyperbranched Polyamidoamine Modified by β-Cyclodextrin

2013 ◽  
Vol 718-720 ◽  
pp. 267-270
Author(s):  
Xiao Long Jiang ◽  
Mi Zhou ◽  
Xiao Feng Ye ◽  
Xin Qian
Keyword(s):  
Michael Addition ◽  
Hyperbranched Polymer ◽  
Inclusion Complexation ◽  
The Novel ◽  
Drug Encapsulation ◽  
H Nmr ◽  
Potential Applications ◽  
Ester Aminolysis ◽  
The Michael Addition ◽  
Ubbelohde Viscometer

h-PAMAM-COOMe and its β-CD derivatives (h-PAMAM-CD) were synthesized step by step via the Michael addition and ester-aminolysis reaction from hyperbranched polyamidoamine (h-PAMAM). The structures of the as-prepared polymers were confirmed by Ubbelohde viscometer, FTIR, and 1H NMR. A series of inclusion complexation formed by β-naphtol in increasing h-PAMAM-β-CD with different concerntration were investigated by UV-vis spectrometer. The result showed that the novel hyperbranched polymer might have potential applications as delivery materials in chemotherapy.

Hyperbranched poly(amine-ester) polyol: Synthesis, characterization, thermal stability, solubility and surface activity

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Wang Xuechuan ◽  
Yuan Xuzheng ◽  
Qiang Taotao ◽  
Chen Xing
Keyword(s):  
Thermal Stability ◽  
Surface Activity ◽  
Michael Addition ◽  
Addition Reaction ◽  
Gel Permeation Chromatography ◽  
Polyol Synthesis ◽  
Michael Addition Reaction ◽  
H Nmr ◽  
Hyperbranched Poly ◽  
The Michael Addition

AbstractA series of hyperbranched poly(amine-ester) polyols were synthesized by the polycondensation of N,N-diethylol-3-amine-methylpropionate [prepared by the Michael addition reaction of methyl acrylate (MA) with diethanolamine (DEA)] as an AB2-type monomer with trimethylol propane (TMP) as the core moiety, proceeding in one-step procedure in the melt with p-toluenesulfonic acid (p-TSA)as catalyst. The Michael addition reaction and polycondensation behaviors were systematically investigated, in an effort to optimize the reaction conditions, respectively. Optimum parameters for addition reaction: at MA/DEA ratio of 2:1 for 4 h at 35 °C, adding MA to DEA, using methyl alcohol as solvent; and for polymerization: dosage of p-TSA was 2 wt % (based on total weight of AB2-type monomer and core) for 4~5 h at 120 °C, adding monomer to core. The obtained monomer and polymers were characterized by Fourier transform infrared spectroscopy (FTIR), 1H-NMR spectroscopy and gel permeation chromatography (GPC). It was suggested that the hyperbranched poly(amine-ester) polyol formed via a mechanism of a combination of transesterification and addition reactions. The thermal stability, solubility and surface activity in aqueous solution of the polymers were also examined.

BODIPY Fluorophores for Membrane Potential Imaging

2019 ◽  
Author(s):  
Jenna Franke ◽  
Benjamin Raliski ◽  
Steven Boggess ◽  
Divya Natesan ◽  
Evan Koretsky ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Water Solubility ◽  
Water Soluble ◽  
Voltage Sensitivity ◽  
Chemical Transformations ◽  
Direct Modification ◽  
Biological Compatibility ◽  
Meso Position ◽  
Ionizable Groups ◽  
Boron Center

Fluorophores based on the BODIPY scaffold are prized for their tunable excitation and emission profiles, mild syntheses, and biological compatibility. Improving the water-solubility of BODIPY dyes remains an outstanding challenge. The development of water-soluble BODIPY dyes usually involves direct modification of the BODIPY fluorophore core with ionizable groups or substitution at the boron center. While these strategies are effective for the generation of water-soluble fluorophores, they are challenging to implement when developing BODIPY-based indicators: direct modification of BODIPY core can disrupt the electronics of the dye, complicating the design of functional indicators; and substitution at the boron center often renders the resultant BODIPY incompatible with the chemical transformations required to generate fluorescent sensors. In this study, we show that BODIPYs bearing a sulfonated aromatic group at the meso position provide a general solution for water-soluble BODIPYs. We outline the route to a suite of 5 new sulfonated BODIPYs with 2,6-disubstitution patterns spanning a range of electron-donating and -withdrawing propensities. To highlight the utility of these new, sulfonated BODIPYs, we further functionalize them to access 13 new, BODIPY-based voltage-sensitive fluorophores. The most sensitive of these BODIPY VF dyes displays a 48% ΔF/F per 100 mV in mammalian cells. Two additional BODIPY VFs show good voltage sensitivity (≥24% ΔF/F) and excellent brightness in cells. These compounds can report on action potential dynamics in both mammalian neurons and human stem cell-derived cardiomyocytes. Accessing a range of substituents in the context of a water soluble BODIPY fluorophore provides opportunities to tune the electronic properties of water-soluble BODIPY dyes for functional indicators.

Enantioselective Recognition of Chiral Guests by the Water-Soluble Chiral Keplerate {Mo132} Spherical Capsule with 30 Inner Lactate Ligands

2019 ◽  
Author(s):  
Nancy Watfa ◽  
Weimin Xuan ◽  
Zoe Sinclair ◽  
Robert Pow ◽  
Yousef Abul-Haija ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Chiral Recognition ◽  
Association Constants ◽  
Water Soluble ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Dosy Nmr ◽  
Spherical Capsule ◽  
Surface Pores ◽  
Guest Chemistry

Investigations of chiral host guest chemistry are important to explore recognition in confined environments. Here, by synthesizing water-soluble chiral porous nanocapsule based on the inorganic metal-oxo Keplerate-type cluster, {Mo<sub>132</sub>} with chiral lactate ligands with the composition [Mo<sub>132</sub>O<sub>372</sub>(H<sub>2</sub>O)<sub>72</sub>(<i>x-</i>Lactate)<sub>30</sub>]<sup>42-</sup> (<i>x</i> = D or L), it was possible to study the interaction with a chiral guest, L/D-carnitine and (<i>R</i>/<i>S</i>)-2-butanol in aqueous solution. The enantioselective recognition was studied by quantitative <sup>1</sup>H NMR and <sup>1</sup>H DOSY NMR which highlighted that the chiral recognition is regulated by two distinct sites. Differences in the association constants (K) of L- and D-carnitine, which, due to their charge, are generally restricted from entering the interior of the host, are observed, indicating that their recognition predominantly occurs at the surface pores of the structure. Conversely, a larger difference in association constants (K<i><sub>S</sub></i>/K<i><sub>R</sub></i> = 3) is observed for recognition within the capsule interior of (<i>R</i>)- and (<i>S</i>)-2-butanol.

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

2006 ◽  
Vol 71 (10) ◽  
pp. 1470-1483 ◽  
Author(s):  
David Šaman ◽  
Pavel Kratina ◽  
Jitka Moravcová ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Analytical Data ◽  
Chiral Hplc ◽  
Nmr Analysis ◽  
Target Structure ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
H Nmr ◽  
Structure Assignment ◽  
Related Compounds ◽  
C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

Synthesis of N4-Substituted Derivatives of 1-[2-(Phosphonomethoxy)ethyl]cytosine and Its Diisopropyl Ester as a Model Reaction for the Synthesis of N4-Substituted Derivatives of Cidofovir

2005 ◽  
Vol 70 (12) ◽  
pp. 2066-2074 ◽  
Author(s):  
Šárka Chalupová ◽  
Antonín Holý ◽  
Milena Masojídková
Keyword(s):  
Secondary Amine ◽  
Model Reaction ◽  
Aqueous Methanol ◽  
Derivatives Of ◽  
Amine Salts

We have studied the reaction of 1-[2-(phosphonomethoxy)ethyl]cytosine (1) and its diisopropyl ester (2) with triethylammonium hydrogensulfite in 60% aqueous methanol. In the presence of some primary or secondary amine salts, at 25-70 °C, this reaction affords transaminated derivatives 4a-4e and 5a, 5b as main products accompanied by uracil compounds. However, with certain amines the reaction failed.

scholarly journals Enzymes, Reacting with Organophosphorus Compounds as Detoxifiers: Diversity and Functions

2021 ◽  
Vol 22 (4) ◽  
pp. 1761
Author(s):  
Ilya Lyagin ◽  
Elena Efremenko
Keyword(s):  
Phylogenetic Analysis ◽  
Future Development ◽  
Organophosphorus Compounds ◽  
The Body ◽  
Chemical Transformations ◽  
Negative Consequences ◽  
Biological Targets ◽  
Oxidation Reduction ◽  
Structural Differences ◽  
Living Organisms

Organophosphorus compounds (OPCs) are able to interact with various biological targets in living organisms, including enzymes. The binding of OPCs to enzymes does not always lead to negative consequences for the body itself, since there are a lot of natural biocatalysts that can catalyze the chemical transformations of the OPCs via hydrolysis or oxidation/reduction and thereby provide their detoxification. Some of these enzymes, their structural differences and identity, mechanisms, and specificity of catalytic action are discussed in this work, including results of computational modeling. Phylogenetic analysis of these diverse enzymes was specially realized for this review to emphasize a great area for future development(s) and applications.

scholarly journals Water-soluble β-aminobisulfonate building blocks for pH and Cu2+ indicators

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84712-84721 ◽  
Author(s):  
Maria A. Cardona ◽  
Marina Kveder ◽  
Ulrich Baisch ◽  
Michael R. Probert ◽  
David C. Magri
Keyword(s):  
Nmr Spectroscopy ◽  
Building Blocks ◽  
Water Soluble ◽  
Visible Absorption ◽  
H Nmr ◽  
Uv Visible

Two phenyl β-aminobisulfonate ligands characterised by UV-visible absorption, EPR and 1H NMR spectroscopy exhibit evidence for binding with Cu2+ in water and methanol.

Study of the Michael addition of β-cyclodextrin–thiol complexes to conjugated alkenes in water

2005 ◽  
pp. 669-671 ◽  
Author(s):  
N. Srilakshmi Krishnaveni ◽  
K. Surendra ◽  
K. Rama Rao
Keyword(s):  
Michael Addition ◽  
The Michael Addition
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