Structural influence on the intermolecular/intramolecular hydrogen bonding in solid state of substituted leflunomides: evidence by X-ray crystal structure

2005 ◽  
Vol 743 (1-3) ◽  
pp. 103-115 ◽  
Author(s):  
T.K. Venkatachalam ◽  
Y. Zheng ◽  
S. Ghosh ◽  
F.M. Uckun
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Intramolecular Hydrogen Bonding ◽  
X Ray ◽  
Intramolecular Hydrogen ◽  
Structural Influence

Synthesis of 2', 6'-Dihydroxychalcones by Using Tetrahydropyran-2-yl and Trialkylsilyl Protective Groups; the Crystal Structure Determination of 2',6'-Dihydroxy-2,4,6-trimethoxychalcone

1989 ◽  
Vol 42 (7) ◽  
pp. 1103 ◽  
Author(s):  
CO Miles ◽  
L Main ◽  
BK Nicholson
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Silyl Ether ◽  
X Ray ◽  
Protective Groups ◽  
Intramolecular Hydrogen ◽  
First Time ◽  
Mild Acid

Two improved general routes to 2′,6′-dihydroxychalcones are described in which the final step is protective-group removal from O 2′ under mild acid conditions. The first involves base-catalysed condensation of benzaldehydes with 2′-hydroxy-6′-tetrahydropyran-2-yloxyacetophenone, the second ring-opening of 5-hydroxyflavanones with 1,8-diazabicyclo[5.4.0]undec-7-ene in the presence of a trialkylchlorosilane to trap out the chalcone as a bis silyl ether. Chalcones prepared by the first route are 2',6'-dihydroxychalcone (1), and its 4-methoxy (2), 3,4-dimethoxy (3), 3,4,5-trimethoxy (4), and 2,4,6-trimethoxy (5) derivatives. The 4-chloro derivative (6) and the chalcone from hesperetin are prepared by the second method. .The X-ray crystal structure of 2',6'-dihydroxy-2,4,6-trimethoxychalcone (5), the first for a 2',6′-dihydroxychalcone, is reported, the hydrogen involved in intramolecular hydrogen-bonding between the carbonyl and phenolic oxygens being located for the first time for any 2'-hydroxychalcone derivative. The O 6' involved in the intramolecular hydrogen-bonding is also hydrogen-bonded intermolecularly to the hydrogen of the other (2'-)hydroxy group of a neighbouring molecule in the lattice. 13C n.m.r. data are the first reported for a series of 2',6'-dihydroxychalcones.

X-ray crystal structure of 1,1-dimethyl-1-phenacylhydrazinium bromide. Evidence for intramolecular hydrogen bonding

1977 ◽  
Vol 18 (38) ◽  
pp. 3333-3336
Author(s):  
Leslie Lessinger ◽  
Mary K. Killoran ◽  
Jean-Pierre Anselme ◽  
Thomas N. Margulis
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
X Ray ◽  
Intramolecular Hydrogen

Intramolecular hydrogen bonding in N-salicylideneanilines. X-ray diffraction and solid-state NMR studies

1995 ◽  
Vol 91 (1) ◽  
pp. 77 ◽  
Author(s):  
Krzysztof Wozniak ◽  
Heyong He ◽  
Jacek Klinowski ◽  
William Jones ◽  
Teresa Dziembowska ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Solid State Nmr ◽  
Intramolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
Intramolecular Hydrogen

scholarly journals Thermal solid-state Z/E isomerization of 2-alkylidene-4-oxothiazolidines: Effects of non-covalent interactions

2011 ◽  
Vol 76 (3) ◽  
pp. 317-328 ◽  
Author(s):  
Zdravko Dzambaski ◽  
Milovan Stojanovic ◽  
Marija Baranac-Stojanovic ◽  
Dragica Minic ◽  
Rade Markovic
Keyword(s):  
Solid State ◽  
1H Nmr Spectroscopy ◽  
Amorphous State ◽  
Intramolecular Hydrogen Bonding ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Configurational Isomerization ◽  
Non Covalent Interactions ◽  
Intramolecular Hydrogen ◽  
Covalent Interactions

Configurational isomerization of stereo-defined 5-substituted and unsubstituted 2-alkylidene-4-oxothiazolidines 1 in the solid state, giving the Z/E mixtures in various ratios, was investigated by 1H-NMR spectroscopy, X-ray powder crystallography and differential scanning calorimetry (DSC). The Z/E composition can be rationalized in terms of non-covalent interactions, involving intermolecular and intramolecular hydrogen bonding and directional non-bonded 1,5-type S...O interactions. X-Ray powder crystallography, using selected crystalline (Z)-4- oxothiazolidine substrates, revealed transformation to the amorphous state during the irreversible Z ? E process. A correlation between previous results on the Z/E isomerization in solution and now in the solid state was established.

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