Serendipitous Formation of 2-Pyrazolo[3,4-]pyridazin-7(6)-ones from 3-Arylsydnones.

Fused nitrogen heterocyclesnamely, pyrazolo[3,4-]pyridazin-7(6)-ones have been obtained by exploiting the 1,3-dipolar nature of -arylsydnones, from hydrazones of 3-aryl-4-acetylsydnones the Vilsmeier-Haack strategy. Facile intramolecular nucleophilic addition followed by CO elimination under reflux or upon microwave irradiation was presented. Plausible mechanisms for the formation of the title compounds are proffered.

Synthesis, Photophysical and Computational Study of Novel Coumarin-based Organic Dyes.

A series of novel coumarin pyrazoline moieties combined with tetrazoles, 3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one, 6-chloro-3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one, 6-bromo-3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one and 6-bromo-3-(1-(4-bromophenyl)-4-(1H-tetrazol-5-yl)-1H pyrazol-3-yl)-2H-chromen-2-one7(a-d), were designed and synthesized. Single crystal X-ray diffraction and their interactions were studied by Hirshfeld surface analysis. Thermal stabilities and electrochemical properties of these compounds were examined from differential scanning calorimetry (DSC), thermogravimetric (TGA) and cyclic voltammetric (CV) studies.

Design and Microwave Assisted Synthesis of Coumarin Derivatives as PDE Inhibitors.

Coumarins appended to benzimidazole through pyrazole are designed and synthesized using microwave irradiation. These compounds were analyzed for phosphodiesterase (PDE) inhibition indirectly by motility pattern in human spermatozoa. Some of the synthesized compounds, namely, 5d, 5e, 5f, 5g, 5h, and 5k, have exhibited potent inhibitory activity on PDE.

1-(4-Chloro-phen-yl)-1H-1,2,4-triazol-5(4H)-one.

In the title compound, C8H6ClN3O, the dihedral angle between the 1,2,4-triazole and benzene rings is 4.60 (9)° and an intra-molecular C-H⋯O inter-action closes an S(6) ring. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R 2 (2)(8) loops and C-H⋯O inter-actions link the dimers into [100] chains.