Inhibitors of endo-α-mannosidase. Part II. 1-Deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin and congeners modified in the mannojirimycin unit

1993 ◽  
Vol 71 (11) ◽  
pp. 1928-1942 ◽  
Author(s):  
Ulrike Spohr ◽  
Mimi Bach ◽  
Robert G. Spiro
Keyword(s):  
Hydrogen Bonds ◽  
Conformational Analysis ◽  
Chemical Shifts ◽  
Hydroxyl Groups ◽  
Enzyme Complex ◽  
Chemical Modifications ◽  
Intermolecular Hydrogen Bonds ◽  
Glycoprotein Processing ◽  
Nuclear Overhauser ◽  
Reported Data

The syntheses of 1-deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin (9) and its 2-deoxy, 2-O-methyl, 4-deoxy, 4-O-methyl, 6-deoxy, 6-O-methyl, N-methyl, and N-propyl congeners are described. Since 9 was previously shown to effectively inhibit endo-α-D-mannosidase, a glycoprotein-processing hydrolase, these chemical modifications were designed to assist in the assessment of intermolecular hydrogen bonds of the inhibitor–enzyme complex. The previously reported data require that all hydroxyl groups of the deoxymannojirimycin unit of 9, namely, OH-2, OH-4, OH-6, and also the NH-5 group, interact with charged and polar groupings of the enzyme, since deoxygenations and alkylations abolished or significantly reduced activities. Conformational analysis of 9 and some of its congeners based on NMR chemical shifts, experimental and theoretical nuclear Overhauser enhancements, and HSEA calculations were performed. The chemical modifications of the glucose unit of 9 are described in the accompanying paper.

Inhibitors of endo-α-mannosidase. Part III. Congeners of 1-deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin modified in the glucose unit

1993 ◽  
Vol 71 (11) ◽  
pp. 1943-1954 ◽  
Author(s):  
Ulrike Spohr ◽  
Mimi Bach
Keyword(s):  
Complex Formation ◽  
Hydrogen Bonds ◽  
Binding Site ◽  
High Specificity ◽  
Enzyme Complex ◽  
Chemical Modifications ◽  
Intermolecular Hydrogen Bonds ◽  
Strong Inhibitor ◽  
Glucose Unit ◽  
Glycoprotein Processing

The syntheses of congeners of 1-deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin (1), a strong inhibitor of the glycoprotein-processing endo-mannosidase, are described. The chemical modifications of 1 involved all monodeoxy-genations and mono-O-methylations of the glucose unit and the replacement of this unit by D-galactose, D-xylose, and 2-chloro-2-deoxy-D-glucose. As reported previously, none of the modifications of 1, including deoxygenations and O- and N-methylations of the deoxymannojirimycin unit, improved the inhibitory properties, but demonstrated the high specificity in the recognition of 1 by the enzyme and allowed the assignment of intermolecular hydrogen bonds of the inhibitor • enzyme complex. Essential for complex formation were found NH-5, OH-2, OH-4, and OH-6 of the DMJ unit, as well as OH-3′, OH-4′, and CH2-6′ of the glucose unit. The residual activities on deoxygenating the OH-2′ and OH-6′ groups of 1 suggest their involvement at the periphery of the binding site.

1-(4-Chlorophenyl)-4-(2-furoyl)-3-(2-furyl)-1H-pyrazol-5-ol

2007 ◽  
Vol 63 (3) ◽  
pp. o1289-o1290 ◽  
Author(s):  
Jin-Zhou Li ◽  
Heng-Qiang Zhang ◽  
Hong-Xin Li ◽  
Pi-Zhi Che ◽  
Tian-Chi Wang
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Intermolecular Hydrogen Bond ◽  
Hydroxyl Groups ◽  
Intermolecular Hydrogen Bonds ◽  
Compound C ◽  
Graph Set

The crystal structure of the title compound, C18H11ClN2O4, contains intra- and intermolecular hydrogen bonds that link the ketone and hydroxyl groups. The intermolecular hydrogen bond results in the formation of a dimer with an R 2 2(12) graph-set motif.

scholarly journals Deprotonation of resorcinarenes and novel ammonium salt complexes

2014 ◽  
Vol 70 (a1) ◽  
pp. C678-C678
Author(s):  
Ngong Beyeh ◽  
Arto Valkonen ◽  
Fanfang Pan ◽  
Kari Rissanen
Keyword(s):  
Hydrogen Bonds ◽  
Binding Sites ◽  
Molecular Complexes ◽  
Ammonium Salts ◽  
Hydroxyl Groups ◽  
Binding Modes ◽  
Intermolecular Hydrogen Bonds ◽  
Guest Molecules ◽  
Cone Conformation ◽  
Intramolecular Hydrogen

The bowl shape cavity of resorcinarenes usually stabilized by four intramolecular hydrogen bonds offers an interesting array of binding modes such as C–H...π and cation...π interactions to recognize a variety of guests. The multiple hydroxyl groups can participate in a series of intermolecular hydrogen bonds with guest molecules. This unique cone conformation of resorcinarenes has led to the synthesis of many receptors with convergent arrangement of binding sites suitable for molecular recognition in many applications. Unfunctionalized resorcinarenes are known to easily form molecular complexes with guests of varying shapes and sizes. Amines are very common bases used in many catalytic processes. A good example is the use of amines as bases in the alkylation and acylation of resorcinarenes leading to cavitands, carcerands, hemicarcerands and velcrands. The use of amines in such reactions is to deprotonate the resorcinarene hydroxyl groups, hence facilitating the alkylation and acylation processes. The subsequently protonated ammonium cation then forms interesting supramolecular complexes with the anionic and dianionic resorcinarenes. Furthermore, secondary and tertiary ammonium salts possess hydrogen bond donating -NH2 and -NH respectively and these can further enhance their complexation through intermolecular hydrogen bonds. Here we present our recent examples of supramolecular assemblies resulting from the deprotonation of resorcinarenes by mono- and dibasic amines. Also, our latest supramolecular co-crystals between resorcinarenes as the receptors and a series of secondary and tertiary mono- and diammonium cations are illustrated.

Conformational Analysis of Poly(ethylene imine) and Its Model Compounds:  Rotational and Inversional Isomerizations and Intramolecular and Intermolecular Hydrogen Bonds

2004 ◽  
Vol 37 (24) ◽  
pp. 9169-9183 ◽  
Author(s):  
Yuji Sasanuma ◽  
Satoshi Hattori ◽  
Shinichi Imazu ◽  
Satoshi Ikeda ◽  
Tomoyoshi Kaizuka ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Conformational Analysis ◽  
Model Compounds ◽  
Ethylene Imine ◽  
Intermolecular Hydrogen Bonds ◽  
Poly Ethylene

Quantification of Intramolecular Hydrogen Bond in Neurotransmitter Dopamine

2009 ◽  
Vol 2 (3) ◽  
pp. 671-674
Author(s):  
Nagaraju Garipelli ◽  
RB Sunoj ◽  
Madhava Reddy B ◽  
Jithan AV ◽  
Chinnalaliah Runja
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Conformational Analysis ◽  
Intramolecular Hydrogen Bond ◽  
Isodesmic Reaction ◽  
Hydroxyl Groups ◽  
Reaction Method ◽  
Aromatic Systems ◽  
Intramolecular Hydrogen ◽  
Different Levels

Dopamine is a catecholamine chemically, 3, 4-dihydroxyphenyethylamine. It has intramolecular H-bond (IHB) between the two hydroxyl groups. The energy of intramolecular H-bond might contribute energy in binding of the neurotransmitter with the receptors. Here the IHB in Dopamine is calculated in different levels of theories. The energetics of intramolecular hydrogen bonds is of fundamental importance in biochemistry. In contrast with intermolecular H-bonds, whose enthalpy can be determined by a supermolecular approach, there is no general accepted procedure to determine the enthalpy of an intramolecular H-bond. In this work, different ways for assessing the energetics of intramolecular H-bonds of selected aromatic systems were applied and compared. They include the widely used conformational analysis approach (cis-trans method), a recently proposed isodesmic reaction method, and a new procedure that is designated as the ortho-para method.

scholarly journals allo-Inositol

2006 ◽  
Vol 62 (7) ◽  
pp. o2578-o2579
Author(s):  
Arnaud Bonnet ◽  
William Jones ◽  
W. D. Samuel Motherwell
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Chair Conformation ◽  
Hydroxyl Groups ◽  
Intermolecular Hydrogen Bonds ◽  
Compound C ◽  
Hydrogen Bond Donors

In the crystal structure of the title compound, C6H12O6, molecules adopt a chair conformation. The H atoms were located and their positions refined satisfactorily. The molecules form one intramolecular and 12 intermolecular hydrogen bonds; all hydroxyl groups act as hydrogen-bond donors and acceptors.

Molecular recognition X. A novel procedure for the detection of the intermolecular hydrogen bonds present in a protein•oligosaccharide complex

1992 ◽  
Vol 70 (1) ◽  
pp. 241-253 ◽  
Author(s):  
P. V. Nikrad ◽  
H. Beierbeck ◽  
R. U. Lemieux
Keyword(s):  
Crystal Structure ◽  
Molecular Recognition ◽  
Hydrogen Bonds ◽  
Aqueous Phase ◽  
Hard Sphere ◽  
Hydroxyl Groups ◽  
Intermolecular Hydrogen Bonds ◽  
Methyl Derivatives ◽  
Derivatives Of ◽  
Hydrogen Bonded

The relative potencies of both the monodeoxy and mono-O-methyl derivatives of the Leb-OMe tetrasaccharide (α-L-Fuc-(1 → 2)-β-D-Gal-(1 → 3)-[α-L-Fuc-(1 → 4)]-β-D-GlcNAc-OMe) as inhibitors of the complexation of a Leb artificial antigen by the lectin IV of Griffoniasimplicifolia are interpreted in terms of the X-ray crystal structure at 2.5 Å resolution of the GS-IV • Leb-OMe complex. Both kinds of derivatives maintain high potencies when the hydroxyl groups involved appear, in the crystal structure, to be in contact with the aqueous phase. Hydroxyl groups situated at the periphery of the combining site and hydrogen bonded to the protein can also be deoxygenated without important loss in potency. However, their methylation leads to a strong decrease in the stability of the complex, because the steric bulk of the introduced methyl group causes loss of complementarity. In contrast, the hydroxyl groups that form hydrogen bonds with the protein along the base of the shallow amphiphilic cleft of the combining site can neither be deoxygenated nor methylated without virtually complete loss of binding activity. Thus, the procedure can provide an appreciation of the various kinds of hydrogen bonds that are present in a protein • oligosaccharide complex. Hard-sphere calculations supported these contentions since an energetically favorable orientation was indicated for a methoxy group at any one of the five positions that were expected to remain in contact with the aqueous phase. However, the calculations, as expected, showed the introduction of strong destabilizing nonbonded interactions when the methylation involved hydroxyl groups that are hydrogen bonded to the protein in the complex. The results are in accord with the previously made rationalization of the near linear enthalpy–entropy compensation found for the active deoxy congeners. Keywords: molecular recognition, lectin IV of Griffoniasimplicifolia, O-methyl derivatives of the Lewis b-OMe tetrasaccharide, detection of intermolecular hydrogen bonds, hard-sphere calculations.

Etude spectroscopique des dérivés du peroxyde d'hydrogène. IV. L'acide de Caro, H2SO5

1970 ◽  
Vol 48 (24) ◽  
pp. 3903-3910 ◽  
Author(s):  
José L. Arnau ◽  
Paul A. Giguère
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonding ◽  
Hydroxyl Groups ◽  
Intermolecular Hydrogen Bonds ◽  
Laser Raman ◽  
Laser Raman Spectra ◽  
Intramolecular Hydrogen ◽  
First Time ◽  
Lattice Modes

The i.r. and laser Raman spectra of pure, crystalline Caro's acid, H2SO5, were measured for the first time between 4000 and 30 cm−1. Most of the fundamental vibrations of the molecule could be identified by comparison with those of the H2SO4, H2O2 and HSO5− species. In addition, a dozen or so of lattice modes were recorded. The O—O stretching frequency is slightly higher (886 cm−1) than in solid H2O2, contrary to expectation. The two hydroxyl groups are quite different, both chemically (Caro's acid is essentially monobasic) and spectroscopically. The ionizable OH group forms strong intermolecular hydrogen bonds, as in H2SO4. However, the non-ionizable O2H group is engaged mainly in intramolecular hydrogen bonding. The unit cell of the crystalline acid must contain more than two molecules.

A Crystallographic Study of Bis[S-benzyl-5-bromo-2-oxoindolin-3-ylidenemethanehydrazonthioate] Disulfide Solvated with Dimethylsulfoxide

2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Site Occupancy ◽  
Unit Cell Parameters ◽  
Intermolecular Hydrogen Bonds ◽  
Triclinic Space Group ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Thiol Form

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.

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