Thiazoloisoquinolines. III. Structure and methylation of 2-hydroxythiazolo[4,5-c]- and -[5,4-c]isoquinolines

1968 ◽  
Vol 46 (5) ◽  
pp. 691-694 ◽  
Author(s):  
Catherine E. Hall ◽  
Alfred Taurins
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Methyl Iodide ◽  
Dimethyl Sulfate ◽  
The Other ◽  
Thiazole Ring ◽  
Spectral Evidence ◽  
Other Hand ◽  
Methylating Agents ◽  
Nuclear Magnetic

2-Hydroxythiazolo[4,5-c]isoquinoline (1) and 2-hydroxythiazolo[5,4-c]isoquinoline (2) were both found to exist predominantly in the lactam form (1b and 2b respectively) from infrared, nuclear magnetic resonance, and ultraviolet spectral evidence. Various methylating agents methylated compound 1 exclusively on the N-3 atom in the thiazole ring. Compound 2 on the other hand, gave a mixture of O-and N-3 methylated products with diazomethane and a mixture of N-1 and N-4 methylated products with either methyl iodide or dimethyl sulfate.

FORMATION OF DIASTEREOISOMERIC ORTHOACETATES OF D-MANNOSE: N.M.R. SPECTRAL EVIDENCE

1963 ◽  
Vol 41 (2) ◽  
pp. 399-406 ◽  
Author(s):  
A. S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Acid Hydrolysis ◽  
Chemical Shifts ◽  
Isomer Ratio ◽  
Methyl Group ◽  
Major Isomer ◽  
Spectral Evidence ◽  
Ratio Data ◽  
Nuclear Magnetic

Diastereoisomeric 1,2-orthoacetates of D-mannose are formed under conditions of the Königs–Knorr synthesis. This is shown by the isolation of two crystalline isomers of β-D-mannose 1,2-(benzyl orthoacetate), and also by examination of the nuclear magnetic resonance (n.m.r.) spectra of several D-mannose orthoacetates. The diastereoisomers show notable differences in respective chemical shifts for the C-methyl and other protons and these variations, together with isomer-ratio data, suggest that the major isomer of a given pair possesses the configuration in which the C-methyl group is endo- and the OR group is exo-. On acid hydrolysis the orthoacetates yield mainly 2-O-acetyl-D-mannose, the structure of which is confirmed by n.m.r. spectral evidence.

NUCLEAR MAGNETIC RESONANCE SPECTRA OF GLYCOL-CLEAVAGE OXIDATION PRODUCTS OF METHYL ALDOPENTOPYRANOSIDES

1966 ◽  
Vol 44 (15) ◽  
pp. 1757-1764 ◽  
Author(s):  
A. S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Deuterium Oxide ◽  
Periodate Oxidation ◽  
Chair Conformation ◽  
The Other ◽  
Oxidation Products ◽  
Hydroxyl Group ◽  
Resonance Spectroscopy ◽  
Nuclear Magnetic

The products obtained by the periodate oxidation of methyl α- and β-D-xylopyranosides have been examined by nuclear magnetic resonance spectroscopy. In deuterium oxide each product exists mainly in two forms, one of which is a hydrated dialdehyde and the other a hemialdal (1,4-dioxane derivative). In dimethyl sulfoxide the dialdehyde cyclizes slowly to yield the hemialdal which, at equilibrium, is found to be by far the most stable of the many isomeric forms possible. The spectrum of this hemialdal in both solvents provides an example of a degenerate ABX type of pattern. The spectra of the products prepared from 5-deuterated xylosides show that the 1-methoxyl group of each hemialdal is axial and the 4-hydroxyl group equatorial, and that the one derived from the β-anomer possesses an inverted chair conformation relative to that of the other hemialdal and of the glycoside itself. The 2-hydroxyl group of each hemialdal appears to be axially oriented. The data support the long-standing view that glycol scission of anomeric aldopentopyranosides leads to products that are mirror images.It has been found also that each product yields a mixture of several p-nitrobenzoates.

1,2,4-Triazines. III. The Methylation of 5,6-Dimethyl-1,2,4-triazin-3-amine and Related Compounds and the Identification of the Products by Carbon-13 Nuclear Magnetic Resonance Spectroscopy

1987 ◽  
Vol 40 (12) ◽  
pp. 1979 ◽  
Author(s):  
NW Jacobsen ◽  
I Dejonge
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Methyl Iodide ◽  
Resonance Spectroscopy ◽  
Reliable Technique ◽  
Related Compounds ◽  
Nuclear Magnetic

5,6-Dimethyl-1,2,4-triazin-3-amine reacts with methyl iodide to give 3-amino-1,5,6-trimethyl-1,2,4-triazinium iodide and 2,5,6-trimethyl-l,2,4-triazin-3(2H)- imine hydriodide . The products were identified by classical methods and confirmed by 13C n.m.r, spectroscopy to establish this as a reliable technique for determining the sites of methylation in such systems. The methylation products from other alkyl-and aryl-substituted 1,2,4-triazin-3-amines are also reported.

Nuclear magnetic resonance studies of the solution chemistry of metal complexes. XVII. Formation constants for the complexation of methylmercury by sulfhydryl-containing amino acids and related molecules

1981 ◽  
Vol 59 (10) ◽  
pp. 1505-1514 ◽  
Author(s):  
R. Stephen Reid ◽  
Dallas L. Rabenstein
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Formation Constants ◽  
Solution Chemistry ◽  
The Other ◽  
Mercaptoacetic Acid ◽  
Resonance Spectroscopy ◽  
Mercaptosuccinic Acid ◽  
Wide Range ◽  
Nuclear Magnetic

Complexation of methylmercury, CH3Hg(II), by mercaptoacetic acid, mercaptoethanol, mercaptosuccinic acid, cysteine, penicillamine, homocysteine, and N-acetylpenicillamine has been studied by 1H nuclear magnetic resonance spectroscopy. The equilibrium constant for displacement of mercaptoacetic acid from its CH3Hg(II) complex by each of the other thiols was measured over a wide range of pH. From the displacement constants and a literature value for the formation constant of the mercaptoethanol complex of CH3Hg(II), formation constants were calculated for thiol complexes with the other ligands, including microscopic formation constants for cysteine and penicillamine complexes in which the amino groups are protonated and deprotonated. Detailed information on the acid–base chemistry of the free amino and carboxylic acid groups in the complexes is also reported. The formation constants increase as the Brønsted basicity of the deprotonated sulfhydryl group increases according to the relation log Kf = pK + 6.86. The conditional formation constants of the CH3Hg(II) complexes are strongly pH dependent due to competitive reactions involving hydrogen and hydroxide ions at low and high pH. The results at physiological pH are discussed with reference to the effectiveness of mercaptosuccinic acid, N-acetylpenicillamine, and penicillamine as antidotes for methylmercury poisoning.

Diastereoisomeric 2-aryl-6-methyl-3,4 (1,2-piperido)-oxazines

1968 ◽  
Vol 46 (7) ◽  
pp. 1105-1111 ◽  
Author(s):  
G. A. Cooke ◽  
G. Fodor
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Catalytic Hydrogenation ◽  
Optically Active ◽  
The Other ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The alkaloid sedridine (1) is formed stereospecifically by catalytic hydrogenation of optically active α-picolyl methyl carbinol (2). The levorotatory 1 gave on action of p-nitro benzaldehyde two μ-aryl oxazines, one crystalline and levorotatory, the other oily and dextrorotatory. This is the first example where both epimers of a μ-aryl oxazine could be detected. The configurations and the conformations of these isomers (10 and 11) and those of sedridine have been discussed in terms of their nuclear magnetic resonance spectra, with particular reference to spin-decoupling evidence.

Distribution of sterols in fungi. II. Brassicasterol in Tuber and Terfezia species

1985 ◽  
Vol 31 (12) ◽  
pp. 1127-1130 ◽  
Author(s):  
J. D. Weete ◽  
M. Kulifaj ◽  
C. Montant ◽  
W. R. Nes ◽  
M. Sancholle
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dry Weight ◽  
The Other ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Fruiting Bodies ◽  
Tuber Species ◽  
Yeastlike Cells ◽  
Nuclear Magnetic

Sterols from ascocarps of Tuber (truffle) and Terfezia species were identified by gas–liquid chromatography, gas chromatography – mass spectrometry, and 1H nuclear magnetic resonance, and the structure of brassicasterol from the yeastlike cells of Taphrina deformans confirmed by 1H nuclear magnetic resonance. Sterols of the fruiting bodies ranged from 1.2 to 2.3 μg/mg dry weight. Ergosterol was the principal sterol of Tuber species which also contained 28–44% brassicasterol depending on the species and source of the sample. Terfezia sp., on the other hand, contained about 98% brassicasterol with only small amounts of ergosterol. Brassicasterol is common to several families of the subdivision Ascomycotina, and to our knowledge has not been reported for a nonascomycetous species.

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