Mohammed Benchidmi

Reactions of 2-Pyrones with 7-Aminoindazole: The First Synthesis of N-(1H-7-Indazolyl)-pyridinones

Abstract New N-(1H-7-indazolyl)-pyridinones have been prepared by the condensation of 2-pyrone derivatives with 7-aminoindazole in the presence of acid medium. They have been characterized by means of 1H and 13C NMR, IR, and mass spectroscopy. The structure of the compounds and the mechanism of their formation are reported.

1-Allyl-6-nitro-1H-indazole.

The fused five- and six-membered rings in the title molecule, C10H9N3O2, are essentially coplanar, the largest deviation from the mean plane being 0.012 (1) Å for the C atom linked to the nitro group. The fused-ring system makes a dihedral angle of 11.34 (6)° with the nitro group, leading to a syn-periplanar conformation. The plane through the atoms forming the allyl group is nearly perpendicular to the indazole fused-ring system, as indicated by the dihedral angle of 73.3 (5)°. In the crystal, each molecule is linked to its symmetry equivalent about the center of inversion by pairs of non-classical C—H⋯O hydrogen bonds, forming an extended tape motif parallel to the (-12-1) plane.

Crystal structure of triethyl 2-(5-nitro-2H-indazol-2-yl)propane-1,2,3-tri­carboxyl­ate

In the title compound, C19H23N3O8, the 5-nitro-2H-indazol-2-yl unit is almost planar, with the maximum deviation from the mean plane being 0.024 (2) Å. The fused-ring system is nearly perpendicular to the three carboxylate groups, with dihedral angles of 90.0 (3), 83.8 (1) and 80.4 (1)°. The ethyl groups attached to both ends of the propane chain are each disordered over two sets of sites, with site-occupancy ratios of 0.425 (17):0.575 (17) and 0.302 (15):0.698 (15). In the crystal, molecules are linked by pairs of C—H⋯N hydrogen bonds, forming inversion dimers. The dimers are further linked by C—H⋯O hydrogen bonds, forming a three-dimensional network.

Synthesis of New Pyrazolo[1.5.4-de]quinoxalines

New pyrazolo[1.5.4-de]quinoxaline derivatives were prepared by the action of 7-aminoindazole 1 on diethyl and dimethyl acetylene dicarboxylates. The structures of the obtained compounds and the direction of cyclization were investigated through a crystallographic study of compound 2. Further alkylation, hydrogenation, and bromination were also explored. The action of potassium thiocyanate on the obtained halo product led to a tetracyclic compound of 1.3-thiazolo[3.4-a]pyrazolo[1.5.4-de]quinoxaline series.

Synthèse de nouveaux dérivés du 1-hydroxyindole et du pyrazole

Abstract New 1-hydroxyindole derivatives have been synthesised by alkylation, acylation reactions and by condensation with acetylacetone and dehydroacetic acid. Action of hydrazines on 3-acetyl-1-hydroxy-indole leads to new pyrazole derivatives.