5′-Nitro-1,4-dihydrospiro[3,1-benzoxazine-2,3′-indolin]-2′-one

Abstract

In the title compound, C15H11N3O4, the six-membered oxazine ring adopts a half-chair conformation and is oriented at an angle of 78.63 (9)° with respect to the pyrrolidine ring of the indoline ring system, which adopts an envelope conformation. The spiro centre C atom is tetrahedral and lies 0.147 (1) Å out of the plane of other four pyrrolidone ring atoms. The nitrobenzene and benzene rings exhibit near planar conformations with C—C—C—N and C—C—C—C torsion angles of 178.1 (2) and 178.8 (2)°, respectively. In the crystal, N—H...O and C—H...O hydrogen bonds connect the molecules, generating a sheet-like structure parallel to the bc plane. Within the sheets, pairs of intermolecular N—H...O hydrogen bonds form inversion dimers enclosing R22(8) ring motifs. In addition, the N—H...O and C—H...O hydrogen bonds generate R32(11) and R22(10) graph-set ring motifs extending the two-dimensional structure. A supramolecular R66(28) loop for each set of six molecules is formed by N—H...O hydrogen bonds within the extended sheet structure and stabilizes the packing. π–π stacking interactions between the nitrobenzene and benzene rings [intercentroid distance = 3.711 (1) Å] and N—O...π interactions further consolidate the crystal packing.

Keywords

• crystal structure
• spirocompounds
• spiro-oxazines
• indoline
• N—H...O and C—H...O hydrogen bonding