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].

Properties of Olean-12-ene-3α,16β,22α,28-tetrol and Some Derivatives

1996 ◽  
Vol 49 (7) ◽  
pp. 775 ◽  
Author(s):  
TW Hambley ◽  
TW Hambley ◽  
KG Lewis ◽  
KG Lewis ◽  
DJ Tucker ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Crystallographic Data ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Ortho Ester ◽  
Polar Solvents ◽  
Space Group ◽  
X Ray ◽  
Intramolecular Hydrogen

Reaction of olean-12-ene-3β,16β,22α,28-tetrol ( chichipegenin ) (1) with methyl orthoformate gives the 16β,22α,28-orthoformate (2). Acetylation of the ortho ester followed by hydrolysis gives the tetrol 3β-monoacetate (5). It is shown that intramolecular hydrogen bonding occurs in the tetrol (1) and the 3β-monoacetate (5) in non-polar solvents. X-Ray crystallographic data on the tetrol and its tetraacetate (4) are reported. The tetrol,C30H50O4, M 474.72, crystallized in the orthorhombic space group P 212121 with a 12.363(6), b 31.888(3), c 6.962(3) Ǻ, V 2745(1) Ǻ3, Dc(Z = 4) 1.149 g cm-3, N = N(unique) 2394, No 1878 [I > 1.5σ(I)], Nvar 500; R 0.038, Rw 0.040. The tetraacetate , C38H58O8, M 642.87, crystallized in the monoclinic space group P 21, with a 10.603(2), b 16.569(1), c 10.814(1) Ǻ, β 98.72(1)°, V 1877.9(4) Ǻ3, Dc(Z = 2) 1.137g cm-3 N 3090, Rmerge 4.67% for N(unique) 2917, No 2663 [I > 2.5σ(I)], Nvar 414; R 0.053, Rw 0.050.

Photoelectron studies on intramolecularly hydrogen-bonded systems. I. The photoelectron spectra of cis- and trans-2-aminocyclopentanol, and cis- and trans-2-(N,N-dimethylamino)cyclopentanol

1976 ◽  
Vol 54 (4) ◽  
pp. 642-646 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Hydrogen Bonding ◽  
Ionization Energy ◽  
Lone Pair ◽  
Intramolecular Hydrogen Bonding ◽  
Photoelectron Spectra ◽  
Hydrogen Bonded Systems ◽  
Intramolecular Hydrogen ◽  
Cis And Trans ◽  
Infrared Data ◽  
Hydrogen Bonded

The photoelectron spectra of cis- and trans-2-aminocyclopentanol and cis- and trans-2-(N,N,-dimethylamino)cyclopentanol have been recorded and interpreted. The cis isomers exhibit N lone pair ionizations at higher ionization energy, and O lone pair ionizations at lower ionization energy than their trans isomers.The results are most consistent with the existence and observation of intramolecular hydrogen-bonding in the cis isomers. Infrared data on these systems also show that the cis isomers exist in the intramolecularly hydrogen-bonded state.

Crystal structures of two polymorphic forms of DOTAM-mono-acid dihydrate

2018 ◽  
Vol 74 (5) ◽  
pp. 542-547
Author(s):  
Paul Jurek ◽  
Garry E. Kiefer ◽  
Frank R. Fronczek
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Temperature Structure ◽  
Intermolecular Hydrogen Bonding ◽  
Space Group ◽  
Pendant Arm ◽  
Polymorphic Forms ◽  
Higher Temperature ◽  
Hydrogen Bonding Network ◽  
Intramolecular Hydrogen

The structural chemistry of 2-[4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecan-1-yl]acetic acid dihydrate, C16H31N7O5·2H2O, is described. The macrocyclic compound, also known by the abbreviation DOTAM-mono-acid, crystallized at room temperature and was isolated concomitantly as two polymorphic forms. The structures of both polymorphs were determined at 90 K. The first polymorph crystallized as a zwitterionic dihydrate [systematic name: 4,7,10-tris(carbamoylmethyl)-1-(carboxylatomethyl)-1,4,7,10-tetraazacyclododecan-1-ium dihydrate] in the space group P21/n, with Z′ = 1. The second polymorph crystallized as a zwitterionic dihydrate in the space group P21 at 90 K, with Z′ = 2. The two independent molecules are related by a local center. In each polymorph, the zwitterion is formed between the negatively-charged carboxylate group and the ring N atom that bears the acetate pendant arm. Extensive inter- and intramolecular hydrogen bonding exists in both polymorphic structures. In polymorph 1, an intermolecular hydrogen-bonding network propagating parallel to the a direction creates an infinite chain. A second hydrogen-bonding network is observed through a water molecule of hydration in the b direction. Polymorph 2 also has two intermolecular hydrogen-bonding networks. One propagates parallel to the a direction, while the other propagates in the [\overline{1}10] direction. Increasing the temperature of polymorph 2 yields the same structure at T = 180 K, but the pseudocenter becomes exact at 299 K. The higher-temperature structure has Z′ = 1 in the space group P21/c.

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.

Sign in / Sign up

Export Citation Format

Share Document