A Double Diastereoselective Michael-Type Addition as an Entry to Conformationally Restricted Tn Antigen Mimics

2013 ◽  
Vol 78 (21) ◽  
pp. 10968-10977 ◽  
Author(s):  
Carlos Aydillo ◽  
Claudio D. Navo ◽  
Jesús H. Busto ◽  
Francisco Corzana ◽  
María M. Zurbano ◽  
...  
Keyword(s):  
Tn Antigen ◽  
Conformationally Restricted ◽  
Michael Type Addition

ChemInform Abstract: A Double Diastereoselective Michael-Type Addition as an Entry to Conformationally Restricted Tn Antigen Mimics.

ChemInform ◽  
2014 ◽  
Vol 45 (14) ◽  
pp. no-no
Author(s):  
Carlos Aydillo ◽  
Claudio D. Navo ◽  
Jesus H. Busto ◽  
Francisco Corzana ◽  
Maria M. Zurbano ◽  
...  
Keyword(s):  
Tn Antigen ◽  
Conformationally Restricted ◽  
Michael Type Addition

Dimethylzinc-mediated enantioselective addition of terminal alkynes to 1,2-diketones using perhydro-1,3-benzoxazines as ligands

2021 ◽  
Author(s):  
Elena Prieto ◽  
Rebeca Infante ◽  
Javier Nieto ◽  
Celia Andres
Keyword(s):  
Chiral Ligand ◽  
Terminal Alkynes ◽  
Conformationally Restricted ◽  
Enantioselective Addition

A conformationally restricted perhydro-1,3-benzoxazine derived from (-)-8-aminomenthol behaves as a good chiral ligand in the dimethylzinc-mediated enantioselective monoaddition of aromatic and aliphatic terminal alkynes to 1,2-diketones. The corresponding α-hydroxyketones were...

scholarly journals Reaction of Chalcones with Cellular Thiols. The Effect of the 4-Substitution of Chalcones and Protonation State of the Thiols on the Addition Process. Diastereoselective Thiol Addition

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4332
Author(s):  
Fatemeh Kenari ◽  
Szilárd Molnár ◽  
Pál Perjési
Keyword(s):  
Biological Effects ◽  
Equilibrium Composition ◽  
Deprotonated Form ◽  
Degree Of Ionization ◽  
Thiol Reactivity ◽  
Michael Type Addition ◽  
Ph Conditions ◽  
The Difference ◽  
Initial Reactivity

Several biological effects of chalcones have been reported to be associated with their thiol reactivity. In vivo, the reactions can result in the formation of small-molecule or protein thiol adducts. Both types of reactions can play a role in the biological effects of this class of compounds. Progress of the reaction of 4-methyl- and 4-methoxychalcone with glutathione and N-acetylcysteine was studied by the HPLC-UV-VIS method. The reactions were conducted under three different pH conditions. HPLC-MS measurements confirmed the structure of the formed adducts. The chalcones reacted with both thiols under all incubation conditions. The initial rate and composition of the equilibrium mixtures depended on the ratio of the deprotonated form of the thiols. In the reaction of 4-methoxychalcone with N-acetylcysteine under strongly basic conditions, transformation of the kinetic adduct into the thermodynamically more stable one was observed. Addition of S-protonated N-acetylcysteine onto the polar double bonds of the chalcones showed different degrees of diastereoselectivity. Both chalcones showed a Michael-type addition reaction with the ionized and non-ionized forms of the investigated thiols. The initial reactivity of the chalcones and the equilibrium composition of the incubates showed a positive correlation with the degree of ionization of the thiols. Conversions showed systematic differences under each set of conditions. The observed differences can hint at the difference in reported biological actions of 4-methyl- and 4-methoxy-substituted chalcones.

scholarly journals Hybrid Acrylated Chitosan and Thiolated Pectin Cross-Linked Hydrogels with Tunable Properties

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 266
Author(s):  
Shaked Eliyahu ◽  
Alexandra Galitsky ◽  
Esther Ritov ◽  
Havazelet Bianco-Peled
Keyword(s):  
Electrostatic Interactions ◽  
Profile Analysis ◽  
Hybrid Hydrogel ◽  
Texture Profile ◽  
Ph Values ◽  
X Ray Scattering ◽  
Wide Range ◽  
Michael Type Addition ◽  
Physical And Chemical ◽  
Hydrogel System

We developed and characterized a new hydrogel system based on the physical and chemical interactions of pectin partially modified with thiol groups and chitosan modified with acrylate end groups. Gelation occurred at high pectin thiol ratios, indicating that a low acrylated chitosan concentration in the hydrogel had a profound effect on the cross-linking. Turbidity, Fourier transform infrared spectroscopy, and free thiol determination analyses were performed to determine the relationships of the different bonds inside the gel. At low pH values below the pKa of chitosan, more electrostatic interactions were formed between opposite charges, but at high pH values, the Michael-type addition reaction between acrylate and thiol took place, creating harder hydrogels. Swelling experiments and Young’s modulus measurements were performed to study the structure and properties of the resultant hydrogels. The nanostructure was examined using small-angle X-ray scattering. The texture profile analysis showed a unique property of hydrogel adhesiveness. By implementing changes in the preparation procedure, we controlled the hydrogel properties. This hybrid hydrogel system can be a good candidate for a wide range of biomedical applications, such as a mucosal biomimetic surface for mucoadhesive testing.

Substituted benzamides with conformationally restricted side chains. 5. Azabicyclo[x.y.z] derivatives as 5-HT4 receptor agonists and gastric motility stimulants

1993 ◽  
Vol 36 (6) ◽  
pp. 683-689 ◽  
Author(s):  
Frank D. King ◽  
Michael S. Hadley ◽  
Karen T. Joiner ◽  
Roger T. Martin ◽  
Gareth J. Sanger ◽  
...  
Keyword(s):  
Gastric Motility ◽  
Side Chains ◽  
Receptor Agonists ◽  
Conformationally Restricted ◽  
Substituted Benzamides

Conformationally restricted 2,5-diphenyloxazoles: failure of the electromer model for anomalous amplified spontaneous emission spikes

2006 ◽  
Vol 104 (5-7) ◽  
pp. 957-969 ◽  
Author(s):  
J. Saltiel ◽  
R. A. Ivanov ◽  
D. A. Gormin ◽  
T. S. R. Krishna ◽  
R. J. Clark
Keyword(s):  
Spontaneous Emission ◽  
Amplified Spontaneous Emission ◽  
Conformationally Restricted
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