The title compound, C(14)H(10)N(4)O(5), has an E conformation with respect to the C=N bond. The dihedral angle between the benzene rings is 2.41 (14)°. In the crystal, mol-ecules are linked through N-H⋯O hydrogen bonds to form chains along the c axis. C-H⋯O inter-actions are also present, linking the chains to form a three-dimensional network.

In the title compound, C(12)H(16)N(2)O(4), intra-molecular N-H⋯O and C-H⋯O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. The nitro group is almost coplanar with the benzene ring, forming a dihedral angle of 6.2 (2)°. In the crystal structure, neighbouring mol-ecules are linked together by inter-molecular N-H⋯O and O⋯O inter-actions. Of interest are the short inter-molecular O...

The title compound, C(13)H(9)N(3)O(5), prepared as a solid derivative of 3-nitro-analine via reaction with 4-nitro-benzoyl chloride, crystallizes in a chiral space group. The mol-ecule is non-planar with a dihedral angle of 26.1 (1)° between the two benzene rings. Both nitro groups are twisted slightly out of the plane of their corresponding benzene rings, making dihedral angles of 10.7 (4) and...

The title compound, C(12)H(8)N(2)O(4), crystallizes as a zwitterion in which the pyridyl N atom is protonated. The dihedral angle between the benzene and pyridinium rings is 27.9 (2)°. In the crystal, N-H⋯O hydrogen bonds link adjacent zwitterions into a three-dimensional structure.

Reactions of 2-chloro-4-fluoropyridine (8), 2-chloro-4-nitropyridine (9), and their corresponding N-oxides 7 and 3 with the n-heptanolate anion were investigated in three solvents. The desired 2-chloro-4-heptyloxypyridine-N-oxide (4a) was obtained most efficiently from 3 in DMSO. A reaction of 4a with AcSNa followed by deacetylation with MeONa gave the sodium salt of 4-heptyloxy-1-hydroxypyridi...

Various hydroxypyridine derivatives are endogenous or synthetic photosensitizers which could contribute to solar radiation damage. The study of their excited states could lead to a better understanding of their action mechanisms. We present here the ultraviolet (UV) spectra of the protonated 2-, 3- and 4-hydroxypyridine. These spectra were obtained with an experimental device coupling an electr...

Phenylpyridal- and phenyldipyridal-based scaffolds have been designed and synthesized as novel helical peptide mimetics. The synthesis required optimisation and selective alkylation in producing 2,6-functionalized 3-hydroxypyridine derivatives for a convergent scheme. The pyridine analogues were coupled by a series of Suzuki/Stille types cross-coupling reactions. A series of biaryl and ter-aryl...