Crystal structure and Hirshfeld surface analysis of 6-((E)-2-{4-[2-(4-chlorophenyl)-2-oxoethoxy]phenyl}ethenyl)-4,5-dihydropyridazin-3(2H)-one

The pyridazine ring in the title compound, C20H17ClN2O3, adopts a screw-boat conformation. The whole molecule is flattened, the dihedral angles subtended by the least-squares plane of the central aromatic ring with those of the terminal benzene and pyridazine rings being 15.18 (19) and 11.23 (19)°, respectively. In the crystal, the molecules are linked by pairs of N—H...O bonds into centrosymmetric dimers and by C—H...π contacts into columns. The results of the Hirshfeld surface analysis show that the most prominent interactions are H...H, accounting for 36.5% of overall crystal packing, and H...O/O...H (18.6% contribution) contacts.

Construction of Unusual Indole-Based Heterocycles from Tetrahydro-1H-pyridazino[3,4-b]indoles

Herein, we report the successful syntheses of scarcely represented indole-based heterocycles which have a structural connection with biologically active natural-like molecules. The selective oxidation of indoline nucleus to indole, hydrolysis of ester and carbamoyl residues followed by decarboxylation with concomitant aromatization of the pyridazine ring starting from tetrahydro-1H-pyridazino[3,4-b]indole derivatives lead to fused indole-pyridazine compounds. On the other hand, non-fused indole-pyrazol-5-one scaffolds are easily prepared by subjecting the same C2,C3-fused indoline tetrahydropyridazines to treatment with trifluoroacetic acid (TFA). These methods feature mild conditions, easy operation, high yields in most cases avoiding the chromatographic purification, and broad substrate scope. Interestingly, the formation of indole linked pyrazol-5-one system serves as a good example of the application of the umpolung strategy in the synthesis of C3-alkylated indoles.

Phase I metabolic profiling and unexpected reactive metabolites in human liver microsome incubations of X-376 using LC-MS/MS: bioactivation pathway elucidation and in silico toxicity studies of its metabolites

Metabolites of X-376 were characterized by LC-MS/MS. Pyridazine ring and dichloro-phenyl groups were bioactivated by novel pathways.

Crystal structure, Hirshfeld surface analysis and DFT studies of 2-[5-(4-methylbenzyl)-6-oxo-3-phenyl-1,6-dihydropyridazin-1-yl]acetic acid

The title pyridazinone derivative, C20H18N2O3, is not planar. The phenyl ring and the pyridazine ring are inclined to each other by 10.55 (12)°, whereas the 4-methylbenzyl ring is nearly orthogonal to the pyridazine ring, with a dihedral angle of 72.97 (10)°. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with an R 2 2(14) ring motif. The dimers are linked by C—H...O hydrogen bonds, generating ribbons propagating along the c-axis direction. The intermolecular interactions were additionally investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots. They revealed that the most significant contributions to the crystal packing are from H...H (48.4%), H...O/O...H (21.8%) and H...C/C...H (20.4%) contacts. Molecular orbital calculations providing electron-density plots of HOMO and LUMO molecular orbitals and molecular electrostatic potentials (MEP) were also computed, both with the DFT/B3LYP/6–311 G++(d,p) basis set.

Crystal structure, Hirshfeld surface analysis and DFT studies of 6-[(E)-2-(thiophen-2-yl)ethenyl]-4,5-dihydropyridazin-3(2H)-one

In the title compound, C10H10N2OS, the five atoms of the thiophene ring are essentially coplanar (r.m.s. deviation = 0.0037 Å) and the pyridazine ring is non-planar. In the crystal, pairs of N—H...O hydrogen bonds link the molecules into dimers with an R 2 2(8) ring motif. The dimers are linked by C—H...O interactions, forming layers parallel to the bc plane. The theoretical geometric parameters are in good agreement with XRD results. The intermolecular interactions were investigated using a Hirshfeld surface analysis and two-dimensional fingerprint plots. The Hirshfeld surface analysis of the title compound suggests that the most significant contributions to the crystal packing are by H...H (39.7%), C...H/H...C (17.3%) and O...H/H...O (16.8%) contacts.

Crystal structures and Hirshfeld surface analyses of 4-benzyl-6-phenyl-4,5-dihydropyridazin-3(2H)-one and methyl 2-[5-(2,6-dichlorobenzyl)-6-oxo-3-phenyl-1,4,5,6-tetrahydropyridazin-1-yl]acetate

The asymmetric units of the title compounds both contain one nonplanar molecule. In 4-benzyl-6-phenyl-4,5-dihydropyridazin-3(2H)-one, C17H14N2O, (I), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 46.69 (9)°; the phenyl ring of the benzyl group is nearly perpendicular to the plane of the pyridazine ring, the dihedral angle being 78.31 (10)°. In methyl 2-[5-(2,6-dichlorobenzyl)-6-oxo-3-phenyl-1,4,5,6-tetrahydropyridazin-1-yl]acetate, C20H16Cl2N2O3, (II), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 21.76 (18)°, whereas the phenyl ring of the dichlorobenzyl group is inclined to the pyridazine ring by 79.61 (19)°. In the crystal structure of (I), pairs of N—H...O hydrogen bonds link the molecules into inversion dimers with an R 2 2(8) ring motif. In the crystal structure of (II), C—H...O hydrogen bonds generate dimers with R 1 2(7), R 2 2(16) and R 2 2(18) ring motifs. The Hirshfeld surface analyses of compound (I) suggests that the most significant contributions to the crystal packing are by H...H (48.2%), C...H/H...C (29.9%) and O...H/H...O (8.9%) contacts. For compound (II), H...H (34.4%), C...H/H...C (21.3%) and O...H/H...O (16.5%) interactions are the most important contributions.

Crystal structure and Hirshfeld surface analysis of 4-(4-methylbenzyl)-6-phenylpyridazin-3(2H)-one

In this paper, we describe the synthesis of a new dihydro-2H-pyridazin-3-one derivative. The molecule, C18H16N2O, is not planar; the benzene and pyridazine rings are twisted with respect to each other, making a dihedral angle of 11.47 (2)°, and the toluene ring is nearly perpendicular to the pyridazine ring, with a dihedral angle of 89.624 (1)°. The molecular conformation is stabilized by weak intramolecular C—H...N contacts. In the crystal, pairs of N—H...O hydrogen bonds link the molecules into inversion dimers with an R 2 2(8) ring motif. The intermolecular interactions were investigated using Hirshfeld surface analysis and two-dimensional (2D) fingerprint plots, revealing that the most important contributions for the crystal packing are from H...H (56.6%), H...C/C...H (22.6%), O...H/H...O (10.0%) and N...C/C...N (3.5%) interactions.

Crystal structure and the DFT and MEP study of 4-benzyl-2-[2-(4-fluorophenyl)-2-oxoethyl]-6-phenylpyridazin-3(2H)-one

The title pyridazin-3(2H)-one derivative, C25H19FN2O2, crystallizes with two independent molecules (A and B) in the asymmetric unit. In molecule A, the 4-fluorophenyl ring, the benzyl ring and the phenyl ring are inclined to the central pyridazine ring by 86.54 (11), 3.70 (9) and 84.857 (13)°, respectively. In molecule B, the corresponding dihedral angles are 86.80 (9), 10.47 (8) and 82.01 (10)°, respectively. In the crystal, the A molecules are linked by pairs of C—H...F hydrogen bonds, forming inversion dimers with an R 2 2(28) ring motif. The dimers are linked by C—H...O hydrogen bonds and a C—H...π interaction, forming columns stacking along the a-axis direction. The B molecules are linked to each other in a similar manner and form columns separating the columns of A molecules.

Crystal structure and Hirshfeld surface analysis of ethyl 2-[5-(3-chlorobenzyl)-6-oxo-3-phenyl-1,6-dihydropyridazin-1-yl]acetate

The title pyridazinone derivative, C21H19ClN2O3, is not planar. The unsubstituted phenyl ring and the pyridazine ring are inclined to each other, making a dihedral angle of 17.41 (13)° whereas the Cl-substituted phenyl ring is nearly orthogonal to the pyridazine ring [88.19 (13)°]. In the crystal, C—H...O hydrogen bonds generate dimers with R 2 2(10) and R 2 2(24) ring motifs which are linked by C—H...O interactions, forming chains extending parallel to the c-axis direction. The intermolecular interactions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the most significant contributions to the crystal packing are from H...H (44.5%), C...H/H...C (18.5%), H...O/H...O (15.6%), Cl...H/H...Cl (10.6%) and C...C (2.8%) contacts.