THE TAUTOMERISM OF 2-NITRAMINOPYRIDINES

1953 ◽  
Vol 31 (11) ◽  
pp. 1048-1053 ◽  
Author(s):  
Alfred Taurins ◽  
Silvio J. Viron
Keyword(s):  
Resonance Structures ◽  
Tautomeric Forms ◽  
Methyl Derivatives ◽  
Derivatives Of

The nitration of 2-amino-4,6-dimethylpyridine with a mixture of nitric and sulphuric acids gives 4,6-dimethyl-2-nitramino-5-nitropyridine (III). 2-Nitraminopyridine (I), 4-methyl-2-nitraminopyridine (II), and (III) produce with diazomethane methyl derivatives of their tautomeric nitramino and nitrimino forms. Diazoethane gives with (I) both the expected ethyl derivatives. However, from (II) only the ethyl derivative of the nitramino form has been obtained. Diazopropane produces with (I) or (II) the propyl derivatives of the nitramino forms only. The resonance structures of the two tautomeric forms of 2-nitraminopyridine have been advanced.

The synthesis of the isomeric N-methyl derivatives of murexine

1981 ◽  
Vol 34 (8) ◽  
pp. 1739 ◽  
Author(s):  
CC Duke ◽  
JV Eichholzer ◽  
JK Macleod
Keyword(s):  
Imidazole Ring ◽  
The Other ◽  
Pharmacological Activities ◽  
Tautomeric Forms ◽  
Methyl Derivatives ◽  
Paramagnetic Ions ◽  
Nucella Emarginata ◽  
Derivatives Of

The two isomeric N-methyl derivatives of murexine have been synthesised by independent routes and shown to be different from an 'N- methylmurexine' reportedly isolated from the mollusc Nucella emarginata. 1H n.m.r. studies have shown a marked difference in the extent of binding to paramagnetic ions of the two N-methyl derivatives of murexine in water while pharmacological results show substantially different pharmacological activities of the two isomers. Both results can be rationalized in terms of the observed activities being associated with the presence of one or the other of the tautomeric forms of the imidazole ring.

Physical Properties of TCNQ Salts with N-Methyl Derivatives of Pyridine

1982 ◽  
Vol 85 (1) ◽  
pp. 257-263 ◽  
Author(s):  
A. Graja ◽  
M. Przybylski ◽  
B. Butka ◽  
R. Swietlik
Keyword(s):  
Physical Properties ◽  
Methyl Derivatives ◽  
Derivatives Of

Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

2016 ◽  
Vol 12 (8) ◽  
pp. 295-300
Author(s):  
Olga Kovalchukova ◽  
Amangdam A.T. ◽  
Strashnova S.B. ◽  
Strashnov P.V. ◽  
Romashkina E.P. ◽  
...  
Keyword(s):  
Complex Formation ◽  
Organic Ligand ◽  
Spectrophotometric Titration ◽  
Organic Ligands ◽  
Oh Groups ◽  
Tautomeric Forms ◽  
Theoretical Investigations ◽  
Derivatives Of ◽  
Theoretical Results ◽  
Titration Technique

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data.

Effect of substitution of halogen or N3-methyl derivatives of uridine for uridine in trinucleotide codons on their recognition by aminoacyl-[14C]-tRNA

1968 ◽  
Vol 33 (11) ◽  
pp. 3858-3865 ◽  
Author(s):  
D. Grünberger ◽  
A. Holý ◽  
J. Smrt ◽  
F. Šorm
Keyword(s):  
Methyl Derivatives ◽  
Derivatives Of

Methyl derivatives of furan

1974 ◽  
Vol 39 (11) ◽  
pp. 3109-3116 ◽  
Author(s):  
J. Šrogl ◽  
M. Janda ◽  
I. Stibor ◽  
V. Skála ◽  
P. Trška ◽  
...  
Keyword(s):  
Methyl Derivatives ◽  
Derivatives Of

O'-Methyl derivatives of arabinosylcytosine

1972 ◽  
Vol 46 (4) ◽  
pp. 1734-1741 ◽  
Author(s):  
E. Darżynkiewicz ◽  
J.T. Kuśmierek ◽  
D. Shugar
Keyword(s):  
Methyl Derivatives ◽  
Derivatives Of

Hydrogen bonds in derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea

1991 ◽  
Vol 56 (4) ◽  
pp. 880-885 ◽  
Author(s):  
Oľga Hritzová ◽  
Dušan Koščík
Keyword(s):  
Hydrogen Bonds ◽  
Spectral Studies ◽  
Intramolecular Hydrogen Bonds ◽  
Tautomeric Forms ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Intramolecular hydrogen bonds of the N-H···O=C type have been detected in the derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea on the basis of IR spectral studies. The title compounds can exist in two tautomeric forms.

The synthesis of O-methyl derivatives of 4-thiopentofuranosides and 2,5-anhydropentoses

1976 ◽  
Vol 46 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Theodorus van Es
Keyword(s):  
Methyl Derivatives ◽  
Derivatives Of

P.M.R. spectroscopy of O-methyl derivatives of d-galactopyranose and related compounds in solution in deuterium oxide

1972 ◽  
Vol 23 (2) ◽  
pp. 275-282 ◽  
Author(s):  
E.B. Rathbone ◽  
A.M. Stephen ◽  
K.G.R. Pachler
Keyword(s):  
Deuterium Oxide ◽  
Methyl Derivatives ◽  
Derivatives Of ◽  
Related Compounds
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