Nagappan Sivakumar

Synthesis of highly diversified 1,2,3-triazole derivatives via domino [3 + 2] azide cycloaddition and denitration reaction sequence

In this paper, an elegant synthesis of 1,2,3-triazole derivatives via domino [3 + 2] azide cycloaddition and denitration reaction sequence under catalyst free conditions has been described. Treatment of Baylis–Hillman adducts and their cyclic derivatives from nitroolefins with sodium azide in the absence of catalyst smoothly afforded the 1,2,3-triazole derivatives in excellent yields.

2'-Hy-droxy-methyl-1'-(4-methyl-phen-yl)-2'-nitro-1',2',5',6',7',7a'-hexa-hydro-spiro-[indoline-3,3'-pyrrolizin]-2-one.

In the title compound, C22H23N3O4, the tolyl ring is almost perpendicular [83.86 (7)°] to the best plane through the eight atoms of the pyrrolizidine ring system. The molecular conformation is stabilized by an intramolecular O—H⋯O hydrogen bond. The crystal packing features inversion dimers with R 2 2(8) motifs linked by pairs of N—H⋯O hydrogen bonds.

[4-(4-Meth­oxy­phen­yl)-1-methyl-3-nitro­pyrrolidin-3-yl]methanol

In the title compound, C13H18N2O4, the dihedral angle between the benzene and pyrrolidine (all atoms) rings is 70.6 (1)°. The pyrrolidine ring adopts a half-chair conformation. In the crystal, molecules form chains along the c-axis direction linked by O—H⋯N hydrogen bonds, which are then connected by C—H⋯O interactions, forming a sheet parallel to the bc plane.

1-Methyl-3-(2-methyl-phen-yl)-3a-nitro-1,2,3,3a,4,9b-hexa-hydro-chromeno[4,3-b]pyrrole.

The asymmetric unit of the title compound, C19H20N2O3, contains two independent molecules in both of which the pyrrolidine ring adopts an envelope conformation, but with a C atom as the flap in one molecule and the N atom in the other. The pyran ring adopts a half-chair conformation in both molecules. In the crystal, molecules are linked via C—H⋯O hydrogen bonds and C—H⋯π interactions.

3'-Hy-droxy-methyl-1'-methyl-3'-nitro-4'-(o-tol-yl)spiro-[indoline-3,2'-pyrrolidin]-2-one.

The title compound, C20H21N3O4, crystallizes with two molecules in the asymmetric unit. In both molecules, the pyrrolidine ring adopts an envelope conformation. The crystal structure is stabilized by intermolecular C—H⋯O, N—H⋯O and O—H⋯O hydrogen bonds.