Why Are Silyl Ethers Conformationally Different from Alkyl Ethers? Chair−Chair Conformational Equilibria in Silyloxycyclohexanes and Their Dependence on the Substituents on Silicon. The Wider Roles of Eclipsing, of 1,3-Repulsive Steric Interactions, and of Attractive Steric Interactions

2003 ◽  
Vol 125 (49) ◽  
pp. 15163-15173 ◽  
Author(s):  
Cecilia H. Marzabadi ◽  
J. Edgar Anderson ◽  
Jorge Gonzalez-Outeirino ◽  
Piers R. J. Gaffney ◽  
Christopher G. H. White ◽  
...  
Keyword(s):  
Steric Interactions ◽  
Silyl Ethers ◽  
Conformational Equilibria ◽  
Alkyl Ethers

Selective demethylation of O-aryl glycosides by iridium-catalyzed hydrosilylation

2021 ◽  
Author(s):  
Caleb A. H. Jones ◽  
Nathan D. Schley
Keyword(s):  
Silyl Ethers ◽  
Alkyl Ethers ◽  
Aryl Glycosides

The cleavage of alkyl ethers by hydrosilylation is a powerful synthetic tool for the generation of silyl ethers. Previous attempts to apply this transformation to carbohydrate derivatives have been constrained...

Résonance magnétique nucléaire du carbone-13 de composes oxa- et azabicyclo[3.3.1]- et -[4.2.1]nonaniques

1978 ◽  
Vol 56 (1) ◽  
pp. 85-92 ◽  
Author(s):  
M. Barrelle ◽  
M. Apparu ◽  
C. Gey
Keyword(s):  
Nmr Spectra ◽  
Conformational Equilibrium ◽  
Membered Ring ◽  
The Other ◽  
Supplementary Information ◽  
Hydroxyl Groups ◽  
Steric Interactions ◽  
Conformational Equilibria ◽  
Résonance Magnétique ◽  
Boat Form

Carbon-13 nmr spectra have been recorded for 25 oxa- and azabicyclo[3.3.1]- and -[4.2.1]nonanes. Results obtained for the 9-oxabicyclo[3.3.1]nonanes, 2-substituted by hydroxyl or alkyl- and phenylamino groups, as well as those obtained for the N-alkyl- or N-phenyl-9-azabicyclo[3.3.1]nonan-2-ols, provide supplementary information regarding the previously studied structures of these types. Shielding and deshielding due to γ and δ steric interactions were observed depending on the substituent. The study of the oxabicyclo[4.2.1]nonanes, substituted or not substituted in positions 2 and 7 by hydroxyl groups, and of the azabicyclo[4.2.1]nonanes substituted in position 2 by the same group, yields interesting results on the conformational equilibria in these compounds which is caused by the flexibility of the seven-membered ring. The conformational equilibrium is displaced toward the boat form of the seven-membered ring for the unsubstituted compounds. Gauche conformations are proposed for the other compounds in order to account for the experimental observations; the pure chair and boat forms are excluded. Two ketones also have been studied. [Journal translation]

SuFExable Polymers with Helical Structures Derived from Thionyl Tetrafluoride (SOF4)

2019 ◽  
Author(s):  
Suhua Li ◽  
Gencheng Li ◽  
Bing Gao ◽  
Sidharam P. Pujari ◽  
Xiaoyan Chen ◽  
...  
Keyword(s):  
Functional Polymers ◽  
Polymer Chains ◽  
New Materials ◽  
Helical Structures ◽  
Polymer Backbone ◽  
Silyl Ethers ◽  
Helical Polymer ◽  
Key Characteristics ◽  
Post Modification ◽  
Individual Polymer

The first SuFEx click chemistry synthesis of SOF<sub>4</sub>-derived copolymers based upon the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers) is described. This novel class of SuFEx polymer presents two key characteristics: First, the newly created [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and primed to undergo further high-yielding and precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate the presence of helical polymer structures, which itself suggests a preferential approach of new monomers onto the growing polymer chain upon the formation of the stereogenic linking moiety.

Substituted 4-Formyl-2H-chromen-2-ones: Their Reaction with N-(2,3,4,6-Tetra-Oacetyl- β-D-galactopyranosyl)thiosemicarbazide, Antibacterial and Antifungal Activity of Their Thiosemicarbazone Products

2020 ◽  
Vol 24 (19) ◽  
pp. 2272-2282
Author(s):  
Vu Ngoc Toan ◽  
Nguyen Minh Tri ◽  
Nguyen Dinh Thanh
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Selenium Dioxide ◽  
Antibacterial And Antifungal Activity ◽  
E Coli ◽  
Antibacterial And Antifungal Activities ◽  
Alkyl Ethers ◽  
Antibacterial And Antifungal

Several 6- and 7-alkoxy-2-oxo-2H-chromene-4-carbaldehydes were prepared from corresponding alkyl ethers of 6- and 7-hydroxy-4-methyl-2-oxo-2H-chromen-2-ones by oxidation using selenium dioxide. 6- and 7-Alkoxy-4-methyl-2H-chromenes were obtained with yields of 57-85%. Corresponding 4-carbaldehyde derivatives were prepared with yields of 41-67%. Thiosemicarbazones of these aldehydes with D-galactose moiety were synthesized by reaction of these aldehydes with N-(2,3,4,6-tetra-O-acetyl-β-Dgalactopyranosyl) thiosemicarbazide with yields of 62-74%. These thiosemicarbazones were screened for their antibacterial and antifungal activities in vitro against bacteria, such as Staphylococcus aureus, Escherichia coli, and fungi, such as Aspergillus niger, Candida albicans. Several compounds exhibited strong inhibitory activity with MIC values of 0.78- 1.56 μM, including 8a (against S. aureus, E. coli, and C. albicans), 8d (against E. coli and A. niger), 9a (against S. aureus), and 9c (against S. aureus and C. albicans).

A Facile, Efficient and Chemoseletive Deprotection of Silyl Ethers Using Zinc (II) Trifluoromethanesulfonate

2018 ◽  
Vol 15 (3) ◽  
Author(s):  
Kotthireddy Thirumal Reddy ◽  
Reddymasu Sreenivasulu ◽  
Deekala Veronica ◽  
Choragudi Chandrasekhar ◽  
Kowthalam Anitha ◽  
...  
Keyword(s):  
Silyl Ethers
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