G. Vasuki

(E)-N′-(3,4-Di­meth­oxy­benzyl­idene)nicotinohydrazide monohydrate

In the title hydrated compound, C15H15N3O3·H2O, the nicotinohydrazide molecule adopts a trans conformation with respect to the C=N double bond. The dihedral angle between the benzene and pyridine rings is 5.10 (14)°. In the crystal, the solvent water molecule acts as an acceptor, forming an N—H⋯O hydrogen bond supported by two C—H⋯O contacts. It also acts as a donor, forming bifurcated O—H⋯(O,O) and O—H⋯N hydrogen bonds that combine with the former contacts to form zigzag chains of molecules along the c-axis direction. An additional O—H⋯O donor contact completes a set of six hydrogen bonds to and from the water molecule and connects it to a third nicotinohydrazide molecule. This latter contact combines with weaker C—H⋯O hydrogen bonds supported by a C—H⋯π contact to stack molecules along b in a three-dimensional network.

4-Bromo-N-(4-hy­droxy­benzyl­idene)­aniline

In the title compound, C13H10BrNO, the benzene ring planes are inclined at an angle of 48.85 (17)°, resulting in a nonplanar molecule. A characteristic of aromatic Schiff bases with N-aryl substituents is that the terminal phenyl rings are twisted relative to the HC=N plane. In this case, the HC=N unit makes dihedral angles of 11.1 (4) and 38.5 (3)° with the hydroxybenzene and bromobenzene rings, respectively. In the crystal, the molecules are linked by O—H⋯N hydrogen bonds to form infinite (C8) chains along the b axis.

Crystal structure of ethyl 6-methyl-2-oxo-4-(3,4,5-tri­meth­oxy­phen­yl)-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate

In the title compound, C17H22N2O6, the dihydropyrimidine ring adopts a flattened boat conformation. The dihedral angle between the benzene ring and the mean plane of the dihydropyrimidine ring is 75.25 (6)°. In the crystal, molecules are linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif which are linked through N—H⋯O and weak C—H⋯O hydrogen bonds. These, together with π–π ring interactions [centroid–centroid distance = 3.7965 (10) Å], give an overall three-dimensional structure.

(E)-1-([1,1′-Biphen­yl]-4-yl)-3-(2-methyl­phen­yl)prop-2-en-1-one

In the title molecule, C22H18O, the o-tolyl ring is connected through a conjugated double bond. The molecule adopts an E conformation and the C—C=C—C torsion angle is 178.77 (13)°. The overall conformation may be described by the values of dihedral angles between the different planes. The terminal rings are twisted by an angle of 54.75 (8)°, while the biphenyl part is not planar, the dihedral angle between the planes of the rings being 40.65 (8)°. The dihedral angle between the benzene rings is 14.10 (7)°. There are three weak C—H⋯π interactions found in the crystal structure. No classic hydrogen bonds are observed.

Crystal structure of (E)-1-(4'-meth-oxy-[1,1'-biphen-yl]-4-yl)-3-(3-nitro-phen-yl)prop-2-en-1-one.

The title compound crystallized with two independent molecules in the asymmetric unit. In the crystal, they are linked to one another, forming chains enclosing (10) and (12) ring motifs.

Crystal structure of ethyl 6-chloro­methyl-2-oxo-4-(2,3,4-tri­meth­oxy­phen­yl)-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate

The dihydropyrimidine ring in the title ester adopts a flattened envelope conformation. An intramolecular C—H⋯O hydrogen bond generates an S(6) ring. Molecules are linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers.

Synthesis, spectroscopic characterization and crystal structure of 5-bromo-1-(2-cyano-pyridin-4-yl)-1H-indazole-3-carboxylic acid diethylamide

The title compound 5-bromo-1-(2-cyano-pyridin-4-yl)-1H-indazole-3-carboxylic acid diethylamide, C18H16BrN5O, is prepared from 5-bromoindazole-3-carboxylic acid methylester. N1-arylation is carried out with 4-chloro-2-cyanopyridine and the resulting product is converted to diethylamide by reacting with thionyl chloride and diethylamine. The structure is identified from its FT-IR, 1H NMR, 13C NMR spectroscopy, elemental analysis data and unambiguously confirmed by single crystal X-ray diffraction studies. There are two symmetry independent molecules in the asymmetric unit with no significant differences in bond lengths and angles. The title compound crystallizes in the triclinic system, space group

rac-4a,10b-cis,10b,5c-trans-5-(7-Methyl-2-oxo-2H-chromen-4-yl)-3,4,4a,5,6,10b-hexa-hydro-2H-pyrano[3,2-c]quinoline.

P\bar 1