In the title compound, C(9)H(13)N(2)O(+)·ClO(4) (-), the dihedral angle between the planes of the amide group and the pyridinium fragment is 34.11 (14)°. In the crystal, the cations are connected by N-H⋯O hydrogen bonds between the amide groups into chains extended along the a axis. Hydrogen bonds between the pyridinium N-H group and the perchlorate anions organize the chains into a two-dimensi...

The title compound, C(22)H(22)FN(3), exists as a zwitterion with the negative charge on the dicyano-methanide group and the positive charge on the pyridinium N atom. The mol-ecule adopts a Z conformation about the central C=C bond. The dihedral angle between the pyridinium and benzene rings is 65.65 (5)°. Weak C-H⋯N hydrogen bonding is present in the crystal structure.

In the title salt, C(6)H(9)N(2) (+)·NO(3) (-), the 2-amino-5-methyl-pyridinium cation and the nitrate anion are cyclically linked through pyridinium and amine N-H⋯O hydrogen bonds [graph set R(4) (3)(12)]. These units are extended into a zigzag chain structure lying parallel to the a axis, through a second cyclic R(2) (2)(8) association involving amine N-H⋯O and aromatic C-H⋯O hydrogen bonds to...

In the title coordination polymer, [Cu(C(9)H(8)NO(4))(2)](n), the Cu atom, located on a twofold rotation axis, is four coordinate in a distorted square-planar environment. Each 2,6-dimethyl-pyridinium-3,5-dicarboxyl-ate anion bridges two Cu atoms, forming a two-dimensional coordination polymer. A three-dimensional supra-molecular network is built from N-H⋯O hydrogen bonds involving the pyridini...

This paper describes a convenient approach to the 7-aza-des-A-steroid (6,6a,7,8,9,9a-hexahydro-5H-cyclopenta[h]quinoline) scaffold starting from Grundmann's ketone using two different pyridine annulation protocols. The biological evaluation of the pyridine and pyridinium products revealed that these compounds unexpectedly do not interfere with ergosterol and cholesterol biosynthesis. The pyridi...

The cation of the salt, C(18)H(18)N(2)O(2) (2+)·2NO(3) (-), lies about a twofold rotation axis. The pyridinium ring is almost coplanar with the phenyl-ene ring [dihedral angle between rings = 5.69 (9)°]. The crystal structure shows π-π stacking inter-actions [centroid-centroid distance = 3.70 (1) Å] between the pyridinium rings and the phenyl-ene rings, generating a linear chain structure. The ...

In the title compound, C(6)H(9)N(2) (+)·C(6)H(4)NO(2) (-), the 2-amino-5-methyl-pyridinium cation is essentially planar, with a maximum deviation of 0.023 (2) Å. In the crystal, the cations and anions are linked via strong N-H⋯O hydrogen bonds, forming a two dimensional network parallel to (100). In addition, π⋯π inter-actions involving the pyridinium and pyridine rings, with centroid-centroid ...

The title compound, (C(6)H(8)N)(2)[CuCl(4)], is composed of two 3-methyl-pyridinium cation and one tetra-chloridocuprate(II) anion. The geometry around the copper(II) ion is that of a distorted tetra-hedron. In the crystal structure, the anions and cations are linked by three different N-H⋯Cl hydrogen bonds. In addition, the crystal structure exhibits aromatic π-π inter-actions between the pyri...

A very simple annulation reaction was designed, allowing an imidazole moiety to be fused onto a range of pyridine-based derivatives. The methodology consists of an activation step via the formation of a pyridinium salt to increase the electrophilicity of the pyridine ring, followed by a cascade reaction triggered by a nucleophilic attack of the iminium moiety. Depending on the pyridinium salt, ...

Investigation of recently synthesized suit[3]ane and similar systems shows that photoinduced electron transfer occurs on the picosecond time scale from encapsulated heterocycle to pyridinium-based cage.