In the mol-ecule of the title compound, C(10)H(9)N(3)O(2), the pyrazole ring is approximately coplanar with the amino and carboxyl groups. The phenyl group is twisted by 48.13 (3)° relative to this plane. An intra-molecular N-H⋯O hydrogen bond stabilizes the planar conformation of the mol-ecule. The mol-ecules are linked into two-dimensional sheets by two strong inter-molecular N-H⋯N and O-H⋯O ...

In the title compound, C(2)H(4)N(6)O, the planar [maximum deviation = 0.006 (2) Å] amino-tetra-zole group makes a dihedral angle of 83.65 (8)° with the formamide unit. In the crystal structure, inter-molecular N-H⋯N, N-H⋯O and C-H⋯N hydrogen bonds are responsible for the formation of a three-dimensional network.

The asymmetric unit of the title compound, C(5)H(5)ClN(2)·0.5C(4)H(4)O(4), comprises a neutral 2-amino-5-chloro-pyridine mol-ecule and one half of a fumaric acid mol-ecule which lies on an inversion center. The dihedral angle between the pyridine ring and the plane formed by the fumaric acid mol-ecule is 3.22 (8)°. The 2-amino-5-chloro-pyridine mol-ecule is planar, with a maximum deviation of 0...

The asymmetric unit of the title salt, C10H11N2 (+)·C4H5O4 (-), consists of two independent 5-amino-6-methyl-quinolin-1-ium cations and two 3-carb-oxy-propano-ate anions. Both cations are protonated at the pyridine N atoms and are essentially planar, with maximum deviations of 0.026 (3) and 0.016 (2) Å. In the crystal, the cations and anions are linked via N-H⋯O and O-H⋯O hydrogen bonds, formin...

The title Schiff base compound, C(17)H(13)N(3)O(3), crystallizes in a zwitterionic form and exists in a trans configuration about the C=N bond. The mol-ecule is slightly twisted, the dihedral angle between the benzene ring and naphthalene ring system being 10.80 (9)°. The nitro group is twisted relative to the plane of the benzene ring [dihedral angle = 8.88 (12)°]. Bifurcated intra-molecular N...

In the title compound, C(9)H(8)BrNO, the non-H-atom framework is essentially planar, with a maximum deviation of 0.087 (3) Å. In the crystal, mol-ecules are inter-connected into a three-dimensional network by C-H⋯O and N-H⋯O hydrogen bonds. In addition, C-H⋯π inter-actions and a π-π stacking inter-action, with a centroid-centroid distance of 3.5535 (19) Å, are also observed.

In the title compound, C(9)H(10)N(4), the phenyl and triazole rings make a dihedral angle of 38.80 (2)°. N-H⋯N hydrogen bonds link the mol-ecules, forming centrosymmetric R(2) (2)(8) rings; these rings are inter-connected through a C(5) chain, building up a zigzag layer parallel to the (100) plane.

An improved procedure for isolation of 5-amino-3-methyl-1,2,4-thiadiazole in pure form on a multi-gram scale without chromatography is reported. Its 1H and 13C-NMR and IR data are presented and previously published erroneous data corrected. The molecular structure is confirmed by X-ray diffraction which shows layers consisting of an elaborate two-dimensional hydrogen bonded network of molecules.

In the title salt, C(4)H(5)ClN(3) (+)·C(4)H(3)O(4) (-), the 2-amino-5-chloro-pyrimidinium cation is protonated at one of its pyrimidine N atoms. In the roughly planar (r.m.s. deviation = 0.026 Å) hydrogen malate anion, an intra-molecular O-H⋯O hydrogen bond generates an S(7) ring. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O...

The title compound, C11H10BrNO3, is close to planar with the benzo-furan unit and the ester group subtending a dihedral angle of 5.25 (2)°. The mol-ecular structure features an intra-molecular N-H⋯O inter-action. In the crystal, N-H⋯O hydrogen bonds involving carboxyl O-atom acceptors generate a chain extending along [201].