Sulfate radical-based oxidation of the aminopyralid and picloram herbicides: The role of amino group on pyridine ring

The role of substituted anilines as second coordination sphere ligands of cobalt(II) complexes has been investigated. Chemical shifts of the ligand nuclear magnetic resonance (n.m.r.) spectra arising from pseudo-contact interaction with the paramagnetic cobalt complex have been utilized for this purpose. It has been found that in each case the aniline preferentially occupies a position perpendicular to the three fold symmetry axis of the complex and tends to be aligned with the amino group directed towards the cobalt atom. Electron withdrawing substituents para to the amino group enhance the second coordination sphere binding and electron donating substituents diminish it. These results are consistent with the idea that the structure of the second coordination sphere is determined by electrostatic interaction with the negatively charged ligands comprising the first coordination sphere. There is competition between aniline molecules and solvent molecules for a position in the second sphere with the solvent competing with increasing effectiveness in the series carbon tetrachloride, benzene, and methylene chloride.

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Somatostatin analogs which define the role of the lysine-9 amino group

International journal of peptide & protein research ◽

10.1111/j.1399-3011.1983.tb03079.x ◽

2009 ◽

Vol 21 (1) ◽

pp. 66-73 ◽

Cited By ~ 23

Author(s):

RUTH F. NUTT ◽

DANIEL F. VEBER ◽

PAUL E. CURLEY ◽

RICHARD SAPERSTEIN ◽

RALPH HIRSCHMANN

Keyword(s):

Somatostatin Analogs ◽

Amino Group

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A general synthesis of 5,7-diaminoimidazo[4,5-b]pyridine ribosides ("2-amino-1-deazaadenosines") from 5-amino-4-imidazolecarboxamide riboside (AICA riboside)

Canadian Journal of Chemistry ◽

10.1139/v92-166 ◽

1992 ◽

Vol 70 (5) ◽

pp. 1288-1295 ◽

Cited By ~ 4

Author(s):

John E. Francis ◽

Michael A. Moskal

Keyword(s):

Pyridine Ring ◽

Sodium Hydride ◽

Ring System ◽

Ring Closure ◽

Protecting Groups ◽

Amino Group ◽

Phosphoryl Chloride ◽

Compound A ◽

General Synthesis ◽

Methyl Analog

A short general synthesis of 5-substituted 5,7-diaminoimidazo[4,5-b]pyridines from 5-amino-4-imidazolecarboxamide riboside (AICA riboside) was designed to prepare isosteres of substituted 2-aminoadenosines that are selective adenosine A2 receptor agonists. AICA riboside was converted to a hydroxyl-protected 5-amino-4-imidazolecarbonitrile riboside and reacted with an N,N-disubstituted acetamide in the presence of phosphoryl chloride. Sodium hydride treatment completed the ring closure and introduced the 7-amino group. The hydroxyl protecting groups were removed under standard conditions. N-Substitution of the acetamide by one benzyl moiety led to a 5-N-substituted derivative through hydrogenolysis whereas N,N-dibenzylacetamide led to the 5,7-diamino compound. A 6-methyl analog was obtained from an N,N-disubstituted propionamide. This synthesis may be adapted to other heterocyclic systems, as illustrated by the preparation of an example of the imidazo[4,5-b]pyrrolo[3,2-e]pyridine ring system.

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The Palladium-Catalyzed Heteroarylation of Adamantylalkyl Amines with Dihalogenopyridines: Scope and Limitations

Synthesis ◽

10.1055/s-0036-1590860 ◽

2017 ◽

Vol 49 (22) ◽

pp. 5067-5080 ◽

Cited By ~ 5

Author(s):

Irina Beletskaya ◽

Anton Abel ◽

Alexei Averin ◽

Alexei Buryak ◽

Evgenii Savelyev ◽

...

Keyword(s):

Chlorine Atom ◽

Pyridine Ring ◽

Bromine Atom ◽

Amino Group ◽

Halogen Atoms ◽

Palladium Catalyzed ◽

Selective Substitution ◽

Steric Hindrances

Palladium-catalyzed heteroarylation of adamantylalkyl amines characterized by different steric hindrances at the amino group was carried out using 2,3-, 2,5-, 2,6-, and 3,5-dihalogenopyridines. The dependence of the results of the coupling on the nature of the halogen atoms (bromine, chlorine), their position in the pyridine ring, and on the structure of adamantylalkyl amines was investigated. The application of dichloropyridines or bromochloropyridines was shown to be advantageous over the use dibromopyridines in many cases. Selective substitution of bromine atom in positions 3 and 5 in the presence of chlorine atom in position 2 of the pyridine ring was observed. The possibility of N,N-diheteroarylation of adamantane-containing amines with 2,5-dihalogenopyridines was shown, and diamination of 2,6- and 3,5-dihalogenopyridines was demonstrated.

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