The interaction of dimethyl sulfoxide with N-benzoyl amino acids

1981 ◽  
Vol 34 (9) ◽  
pp. 1869 ◽  
Author(s):  
CW Fong ◽  
HG Grant
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Benzene Ring ◽  
Chemical Shifts ◽  
Side Chain ◽  
Torsional Angle ◽  
Intermolecular Hydrogen Bonding ◽  
Atom Increase ◽  
Self Association

The interaction of dimethyl sulfoxide with N-benzoyl amino acids in deuterochloroform has been investigated by 13C n.m.r. spectroscopy. Examination of the chemical shifts of the benzene ring reveals that intermolecular hydrogen bonding between dimethyl sulfoxide and the amido-hydrogen atom increase the effective steric size of the amino hydrogen, resulting in an increase in the torsional angle between the benzene ring and the C(O)NHCH(R)COOH side chain. Self-association of N- benzoyl amino acids in deuterochloroform occurs largely through two COOH...O=C hydrogen bonds and does not involve intermolecular hydrogen bonding to the N-H proton.

Proton N.M.R. of the muramyl dipeptide adjuvant in dimethyl sulfoxide

1982 ◽  
Vol 35 (3) ◽  
pp. 489 ◽  
Author(s):  
BE Chapman ◽  
M Batley ◽  
JW Redmond
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Chemical Shifts ◽  
Muramyl Dipeptide ◽  
Side Chain ◽  
Active Principle ◽  
Temperature Dependences ◽  
Amide Protons

The active principle of complete Freund's adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine, was studied in the α-anomeric form in dimethyl sulfoxide solutions by 1H n.m.r, at 200 MHz. All resonances except those of the nonanomeric sugar protons were assigned. Temperature dependences of the chemical shifts of the amide protons indicated that the alanyl NH is involved in hydrogen bonding. The isoglutamine β-CH2 protons showed large chemical-shift nonequivalence, an effect consistent with a hydrogen bond to the side chain carboxyl of this residue.

The antioxidant methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

2014 ◽  
Vol 70 (11) ◽  
pp. 1050-1053 ◽  
Author(s):  
Xiang Li ◽  
Zhi-Gang Wang ◽  
Hou-He Chen ◽  
Sheng-Gao Liu
Keyword(s):  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Methyl Acrylate ◽  
Title Compound ◽  
Intermolecular Hydrogen Bonding ◽  
Tert Butyl ◽  
Ester Carbonyl ◽  
Compound C ◽  
Steric Crowding

The title compound, C18H28O3, was prepared by the reaction of 2,6-di-tert-butylphenol with methyl acrylate under basic conditions using dimethyl sulfoxide as the promoter. The structure of this antioxidant indicates significant strain between theortho tert-butyl substituents and the phenolic OH group. In spite of the steric crowding of the OH group, it participates in intermolecular hydrogen bonding with the ester carbonyl O atom.

Molecular Association of Hydrogen Bonding Solutes, o-, m-, and p-Cresol, in Carbon Tetrachloride

1974 ◽  
Vol 52 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Earl M. Woolley ◽  
Dennis S. Rushforth
Keyword(s):  
Hydrogen Bonding ◽  
Carbon Tetrachloride ◽  
Least Squares ◽  
Molecular Association ◽  
Intermolecular Hydrogen Bonding ◽  
Heats Of Dilution ◽  
Self Association

The intermolecular hydrogen-bonding self-association of the three cresols in CCl4 solutions at 25 °C has been investigated by calorimetric means. Calorimetrically determined heats of dilution of each of the cresols in anhydrous CCl4 are interpreted in terms of two different models: (i) dimerization and trimerization self-association reactions, and (ii) dimerization followed by stepwise polymerization self-association reactions. Values of K, ΔH0, and ΔS0 for these reactions are calculated using least-squares and other methods. Results show that o-cresol is clearly less associated in anhydrous CCl4 solution at 25 °C than either m- or p-cresol. Values of K2 and K3 (both based on molar concentrations of solutes) and ΔH20and ΔH30 (kcal) for the reactions [Formula: see text] respectively, are o-cresol: 0.7, 1.3,−3.4,−12.5; m-cresol: 0.8, 5.0,−5.0,−13.6; p-cresol: 0.35, 6.5,−5.5,−13.4. Values of K2 and Ks (both based on molar concentrations of solutes) and ΔH20 and ΔHs0 (kcal) for the reactions [Formula: see text] (all n > 2 with same Ks and ΔHS0), respectively, are o-cresol: 0.7, 1.6, −4.2, −4.5; m-cresol: 1.2, 4.0, −5.0, −4.3; p-cresol: 1.0, 7.0, −3.3, −3.5.

scholarly journals Pressure dependence of side chain 1H and 15N-chemical shifts in the model peptides Ac-Gly-Gly-Xxx-Ala-NH2

2020 ◽  
Vol 74 (8-9) ◽  
pp. 381-399
Author(s):  
Markus Beck Erlach ◽  
Joerg Koehler ◽  
Claudia E. Munte ◽  
Werner Kremer ◽  
Edson Crusca ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pressure Dependence ◽  
Chemical Shifts ◽  
Model Systems ◽  
Random Coil ◽  
Nonlinear Dependence ◽  
Side Chain ◽  
Unfolded Proteins ◽  
Pressure Coefficients ◽  
Compression Effects

Abstract For interpreting the pressure induced shifts of resonance lines of folded as well as unfolded proteins the availability of data from well-defined model systems is indispensable. Here, we report the pressure dependence of 1H and 15N chemical shifts of the side chain atoms in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH2 (Xxx is one of the 20 canonical amino acids) measured at 800 MHz proton frequency. As observed earlier for other nuclei the chemical shifts of the side chain nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The pressure response is described by a second degree polynomial with the pressure coefficients B1 and B2 that are dependent on the atom type and type of amino acid studied. A number of resonances could be assigned stereospecifically including the 1H and 15N resonances of the guanidine group of arginine. In addition, stereoselectively isotope labeled SAIL amino acids were used to support the stereochemical assignments. The random-coil pressure coefficients are also dependent on the neighbor in the sequence as an analysis of the data shows. For Hα and HN correction factors for different amino acids were derived. In addition, a simple correction of compression effects in thermodynamic analysis of structural transitions in proteins was derived on the basis of random-coil pressure coefficients.

Proton Magnetic Resonance Spectra of Some Amphetamines and Related Compounds and Observations on Rotamer Populations

1971 ◽  
Vol 49 (19) ◽  
pp. 3143-3151 ◽  
Author(s):  
K. Bailey ◽  
A. W. By ◽  
K. C. Graham ◽  
D. Verner
Keyword(s):  
Hydrogen Bonding ◽  
Phenyl Ring ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Side Chain ◽  
Amino Group ◽  
Ortho Position ◽  
Electronic Effects ◽  
Related Compounds

Data from the p.m.r. spectra of β-amino-, β-aminohydrochloride-, β-hydroxy-, and β-nitro-α-phenyl-propanes having methyl or methoxy substituants on the phenyl ring (37 compounds in all) are presented. The α and β protons of the side-chain give a pattern usually analyzable as ABX. The data are discussed in terms of correlations of coupling constants and chemical shifts with electronegativity of the substituent groups, steric and electronic effects, and apparent changes in rotamer populations. Hydrogen-bonding between the amino group of amphetamines and a methoxyl function at the ortho position in the phenyl ring is indicated for the salts but not the free bases.

Asymmetric transformation of .alpha.-amino acids promoted by optically active cobalt(III) complexes. 3. Importance of side-chain intramolecular interligand hydrogen bonding on stereoselectivity

1982 ◽  
Vol 21 (12) ◽  
pp. 4138-4143 ◽  
Author(s):  
Motowo. Yamaguchi ◽  
Yoshiyuki. Masui ◽  
Masahiko. Saburi ◽  
Sadao. Yoshikawa
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Optically Active ◽  
Side Chain ◽  
Asymmetric Transformation

scholarly journals 1-(4-Chlorobutanoyl)-3-(2-nitrophenyl)thiourea

2012 ◽  
Vol 68 (6) ◽  
pp. o1801-o1801 ◽  
Author(s):  
Nurziana Ngah ◽  
Maisara Kadir ◽  
Bohari M. Yamin ◽  
M. Sukeri M. Yusof
Keyword(s):  
Hydrogen Bonding ◽  
Benzene Ring ◽  
Title Compound ◽  
Dihedral Angles ◽  
Intermolecular Hydrogen Bonding ◽  
Asymmetric Unit ◽  
Compound C ◽  
Thioamide Group ◽  
Independent Molecules

The asymmetric unit of the title compound, C11H12ClN3O3S, contains two independent molecules with different conformations in which the benzene ring and the thiourea fragment form dihedral angles of 87.28 (12) and 66.44 (10)°. The O atom of the thioamide group is involved in bifurcated N—H...O intra- and intermolecular hydrogen bonding; the latter interaction links the independent molecules into a dimer. In the crystal, N—H...S interactions link the molecules into chains propagating along the c axis.

1H and 13C NMR Spectral Studies on N-(Aryl)-Substituted Acetamides, C6H5NHCOCH3-iXi and 2/4-XC6H4NHCOCH3-iXi (where X = Cl or CH3 and i = 0, 1, 2 or 3)

2003 ◽  
Vol 58 (12) ◽  
pp. 801-806 ◽  
Author(s):  
B. Thimme Gowda ◽  
K. M. Usha ◽  
K. L. Jayalakshmi
Keyword(s):  
Chemical Shift ◽  
Benzene Ring ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spectral Studies ◽  
Side Chain ◽  
1H And 13C Nmr ◽  
Methyl Group ◽  
Solution State

35 N-(Phenyl)-, N-(2/4-chlorophenyl)- and N-(2/4-methylphenyl)-substituted acetamides are prepared, characterised and their NMR spectra studied in solution state. The variation of the chemical shifts of the aromatic protons in these compounds follow more or less the same trend with changes in the side chain. The chemical shifts remain almost the same on introduction of Cl substituent to the benzene ring, while that of methyl group lowers the chemical shifts of the aromatic protons. But only 13C-1 and 13C-4 chemical shifts in these compounds are sensitive to variations of the side chain. The incremental shifts in the chemical shifts of the aromatic protons and carbons due to -COCH3−iXi or NHCOCH3−iXi groups in all the N-(phenyl)-substituted acetamides, C6H5NHCOCH3−iXi (where X = Cl or CH3 and i = 0, 1, 2 or 3) are calculated. These incremental chemical shifts are used to calculate the chemical shifts of the aromatic protons and carbons in all the N-(2/4-chlorophenyl)- and N-(2/4-methylphenyl)-substituted acetamides, in two ways. In the first way, the chemical shifts of aromatic protons or carbons are computed by adding the incremental shifts due to -COCH3−iXi groups and the substituents at the 2nd or 4th position in the benzene ring to the chemical shifts of the corresponding aromatic protons or carbons of the parent aniline. In the second way, the chemical shifts are calculated by adding the incremental shifts due to -NHCOCH3−iXi groups and the substituents at the 2nd or 4th position in the benzene ring to the chemical shift of a benzene proton or carbon, respectively. Comparison of the two sets of calculated chemical shifts of the aromatic protons or carbons of all the compounds revealed that the two procedures of calculation lead to almost the same values in most cases and agree well with the experimental chemical shifts.

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