Intramolecular hydrogen bonding and acidities of nucleoside sugar hydroxyls. Crystal structure and conformation of O2,2'-anhydro-1-.alpha.-D-xylofuranosyluracil

1976 ◽  
Vol 98 (15) ◽  
pp. 4640-4644 ◽  
Author(s):  
George I. Birnbaum ◽  
Jerzy Giziewicz ◽  
Carol P. Huber ◽  
David Shugar
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen

Molecular and crystal structure of azadirachtin-H

1996 ◽  
Vol 52 (1) ◽  
pp. 145-150 ◽  
Author(s):  
T. R. Govindachari ◽  
Geetha Gopalakrishnan ◽  
S. S. Rajan ◽  
V. Kabaleeswaran ◽  
L. Lessinger
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Hydroxyl Group ◽  
Inhibiting Activity ◽  
Nmr Studies ◽  
Rotation Axes ◽  
Intramolecular Hydrogen ◽  
Azadirachtin A

Azadirachtin-H, isolated from the seed kernels of Azadirachta indica (neem), crystallizes in space group I4, Z = 8, with disordered ethyl acetate solvent filling channels along the fourfold rotation axes. The crystal structure determination showed that the previously reported molecular structure deduced from NMR studies was correct except for the stereochemistry at C(11). Azadirachtin-H, which belongs to a group of C-seco-tetranortriterpenoids (C-seco-limonoids) of great interest for their insect antifeedant and ecdysis-inhibiting activity, has some unusual features: the absence of a carbomethoxy group at C(11); the presence of a cyclic hemiacetal function at C(11); the α-orientation of the hydroxyl group on C(11), opposite to that in all other known azadirachtins with a hydroxyl group on C(11), except azadirachtin-I. There is no intramolecular hydrogen bonding. In this crystal the rotation of the two major moieties of the azadirachtin-H molecule about the single connecting C(8)—C(14) bond is quite different from that in azadirachtin-A, whose crystal structure has recently been determined.

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.

1,1-Diphenylbutane-1,3-diol: the First Structurally Characterized Example of an Intramolecularly Hydrogen-Bonded Open-Chain 1,3-diol

1996 ◽  
Vol 49 (11) ◽  
pp. 1251
Author(s):  
CF Carvalho ◽  
DP Arnold ◽  
RC Bott ◽  
G Smith
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Orthorhombic Space Group ◽  
Open Chain ◽  
Space Group ◽  
A Cell ◽  
Intramolecular Hydrogen ◽  
Hydroxy Groups ◽  
Hydrogen Bonded

The crystal structure of the asymmetric 1,3-diol 1,1-diphenylbutane-1,3-diol has been determined and refined to a residual R of 0.039 for 795 observed reflections. Crystals are orthorhombic, space group P212121, with four molecules in a cell of dimensions a 9.625(4), b 16.002(3), c 8.834(3) Ǻ. The compound is unique among the known crystallographically characterized open-chain 1,3-diols in having only intramolecular hydrogen bonding involving the hydroxy groups [O-- -O 2.602(5) Ǻ].

scholarly journals Crystallographic structure, activity prediction, and hydrogen bonding analysis of some CSD-based 3,3'-bis-indole derivatives: A review

2021 ◽  
Vol 12 (4) ◽  
pp. 493-501
Author(s):  
Varun Sharma ◽  
Goutam Brahmachari ◽  
Vivek Kumar Gupta
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Structural Features ◽  
Crystal Structure Analysis ◽  
Crystallographic Structure ◽  
Indole Derivatives ◽  
Biologically Relevant ◽  
Structure Activity ◽  
Intramolecular Hydrogen

Herein we report crystallographic comparison of some geometrical and structural features for a series of biologically relevant bis-indole derivatives. Selected bond distances and bond angles of interest in a series of bis-indole derivatives have been discussed in detail. The biological activity of the substances has been correlated with based the structure-activity relationships (SAR) base which provides the different possibility of activity (Pa) and possibility of inactivity (Pi). For a better understanding of the packing interactions existing among these derivatives, an overview of crystal structure analysis with emphasis on the intramolecular hydrogen bonding in some bis-indole derivatives is presented. The role of hydrogen bonding in the crystal structure assembly of bis-indole derivatives has been found to be predominant and this observation reveals significant impact of hydrogen bonding in high value of drug-likeness of these bio-molecules.

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
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