Intramolecular hydrogen-bonding in 2-nitroresorcinol. A combined FT-IR, FT-Raman and computational study

2000 ◽  
Vol 253 (2-3) ◽  
pp. 193-204 ◽  
Author(s):  
A. Kovács ◽  
G. Keresztury ◽  
V. Izvekov
Keyword(s):  
Hydrogen Bonding ◽  
Computational Study ◽  
Intramolecular Hydrogen Bonding ◽  
Ft Ir ◽  
Intramolecular Hydrogen ◽  
Ft Raman

scholarly journals A simple and effective preparation of quercetin pentamethyl ether from quercetin

2018 ◽  
Vol 14 ◽  
pp. 3112-3121 ◽  
Author(s):  
Jin Tatsuzaki ◽  
Tomohiko Ohwada ◽  
Yuko Otani ◽  
Reiko Inagi ◽  
Tsutomu Ishikawa
Keyword(s):  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Room Temperature ◽  
Computational Study ◽  
Dimethyl Sulfate ◽  
Intramolecular Hydrogen Bonding ◽  
Single Product ◽  
Oh Groups ◽  
Methylation Product ◽  
Intramolecular Hydrogen

Among the five hydroxy (OH) groups of quercetin (3,5,7,3',4'-pentahydroxyflavone), the OH group at 5 position is the most resistant to methylation due to its strong intramolecular hydrogen bonding with the carbonyl group at 4 position. Thus, it is generally difficult to synthesize the pentamethyl ether efficiently by conventional methylation. Here, we describe a simple and effective per-O-methylation of quercetin with dimethyl sulfate in potassium (or sodium) hydroxide/dimethyl sulfoxide at room temperature for about 2 hours, affording quercetin pentamethyl ether (QPE) quantitatively as a single product. When methyl iodide was used in place of dimethyl sulfate, the C-methylation product 6-methylquercetin pentamethyl ether was also formed. A computational study provided a rationale for the experimental results.

Gold(I) 1,2,3-Triazolylidene Complex Featuring the Interaction Between Gold and Methine Hydrogen

2021 ◽  
Author(s):  
Adi Narayana Mannem ◽  
Moulali Vaddamanu ◽  
Arruri Sathyanarayana ◽  
Kumar Siddhant ◽  
Shohei Sugiyama ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Intramolecular Hydrogen Bonding ◽  
Hydrogen Bonding Interaction ◽  
Bonding Interaction ◽  
Ft Ir ◽  
Intramolecular Hydrogen

Mesoionic N-heterocyclic carbene-gold(I) complex with a unique Au····H–C(methine) intramolecular hydrogen bonding interaction has been investigated in the solid-state. The structure of this new neutral gold(I)-carbene was characterized by FT-IR, NMR...

Vibrational Spectroscopy of Certain Polymaleic- and Polyacrylic-Based Mesomorphic Polymers

1995 ◽  
Vol 49 (9) ◽  
pp. 1311-1316 ◽  
Author(s):  
Dimitris Tsiourvas ◽  
Constantinos M. Paleos ◽  
Jane Anastassopoulou ◽  
Theophile Theophanides
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Liquid Crystalline ◽  
Polymeric Materials ◽  
Intramolecular Hydrogen Bonding ◽  
Polar Group ◽  
Smectic Phases ◽  
Carboxylic Groups ◽  
Ft Ir ◽  
Intramolecular Hydrogen

The FT-IR/ATR technique has been employed in the investigation of the forces leading to the organization of a number of polymeric materials exhibiting thermotropic liquid crystalline character. Two types of compounds have been studied, i.e., one bearing the carboxylic polar group near the main chain and the other at the end of the side chain. Intermolecular and intramolecular hydrogen bonding between the carboxylic groups was found to lead to the formation of “facing” and “sideways” structures. Enhanced stability of these supramolecular structures was obtained by the presence of intramolecular hydrogen bonds between the amide groups, resulting in the formation of smectic phases. Furthermore, it has been found that the strengthening of hydrogen bonding between carboxylic groups is associated with a weakening of hydrogen bonds between the amide groups.

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