The title compound, (C(13)H(16)N(4))[ZnCl(4)], consists of a tetra-hedral [ZnCl(4)](2-) anion and a 2-{2-[4-(dimethyl-amino)-phen-yl]diazen-1-ium-1-yl}pyridinium dication. The pyridinium-N atom is syn to the azo bond which allows for the formation of an intramolecular N-H⋯N hydrogen bond. In the crystal, the cation and anion are held together by N-H⋯Cl hydrogen-bond inter-actions involving the ...

3-Phenyl(methyl)-5-alkyl-1-(pyridin-3-yl)imidazo[1,5-a]quinoxalin-4-ones (2a-f) and their N-alkyl-pyridinium salts (3a-o), including 1,n-bis{3-(3-phenylimidazo[1,5-a]quinoxalin-4(5H)-on-1-yl)pyridinium}alkane dibromides (4a-d, 5, 6) have been synthesized. It has been established that the antimicrobial properties of imidazo[1,5-a]quinoxaline derivatives are connected with the presence of various...

Values for the urinary excretion of pyridinium crosslinks of collagen, pyridinoline and deoxypyridinoline, in a group of 30 elderly women with femoral fractures associated with osteoporosis and a group of 20 women without recent fracture but with overt or suspected osteoporosis were compared with 27 control subjects matched for age. Relative to the control group, the excretion of the crosslinks...

In the title complex, (C(5)H(6)ClN(2))(C(7)H(8)NO)[CoCl(4)], the Co(II) ions are tetra-hedrally coordinated. The crystal structure is built from hydrogen-bonded centrosymmetric tetra-mers of tetra-chloridocobaltate(II) dianions and 3-amino-2-chloro-pyridinium cations, additionally strengthened by significant π-π stacking of pyridinium rings [interplanar distance 3.389 (3) Å]. The tetra-mers are...

N-Substituted pyridinium salts constitute one of the most valuable reagent classes in organic synthesis, due to their versatility and ease of use. Herein we report a preliminary synthesis and detailed structural analysis of several N-(1-ethoxyvinyl)pyridinium triflates, an unusual class of pyridinium salts with potentially broad use as a reagent in organic synthesis. Treatment of pyridines with...

Two neurotoxic pyridinium metabolites of haloperidol, 4-(4-chlorophenyl)-1-[4-(4-fluorophenyl)-4-oxybutyl]pyridinium ion (HPP(+)) and 4-(4-(chlorophenyl)-1-4-(fluorophenyl)-4-hydroxybutyl-pyridinium (RHPP(+)), are formed in the liver and found in the brain. To understand how these neurotoxic pyridinium metabolites are distributed in the brain, HPP(+) and RHPP(+) were evaluated as substrates for...

The title compound, (C(6)H(9)N(2))(2)[CuCl(4)], contains a distorted tetra-hedral [CuCl(4)](2-) anion and two protonated amino-pyridinium cations. The geometries of the protonated amino-pyridinium cations reveal amine-imine tautomerism. The crystal packing is influenced by N-H⋯Cl and C-H⋯Cl hydrogen bonds and π-π stacking inter-actions [centroid-centroid distances = 3.635 (4) and 3.642 (4)°].

2-(Pyridinium-1-yl)-1,1-bis(triflyl)ethanides have been used as 1,2-dipole precursors in a metal-free direct [2+2] cycloaddition reaction of alkynes. Starting from stable zwitterionic pyridinium salts, the electron deficient olefin 1,1-bis(trifluoromethylsulfonyl)ethene is generated in situ and immediately reacted at room temperature with an alkyne to afford substituted cyclobutenes. Remarkably...

Reactivation of organophosphate (OP)-inhibited acetylcholinesterase (AChE) by oximes is the primary reason for their effectiveness in the treatment of OP poisoning. Reactivation is reported to accelerate by quaternary ligands such as decamethonium, which is devoid of nucleophilicity. The mechanism of this enhancement is not known. To better understand the acceleration phenomenon, we examined li...