4′-Methyl-1H-14′,19′-dioxa-4′-azaspiro[indole-3,5′-tetracyclo[18.4.0.02,6.08,13]tetracosane]-1′(24′),8′,10′,12′,20′,22′-hexaene-2,7′(3H)-dione

In the title compound, C29H28N2O4, the indoline ring system is essentially planar, with a maximum deviation of 0.027 (2) Å; the carbonyl O atom lies 0.102 (1) Å out of the least-squares plane of the indole ring. The pyrrolidine ring adopts a C-envelope conformation, with a C atom displaced by 0.643 (2) Å from the mean plane formed by the remaining ring atoms. The pyrrolidine ring makes a dihedral angle of 86.1 (8)° with the indoline ring system. In the crystal, N—H⋯O hydrogen bonds result in the formation of cyclic centrosymmetric dimers [R 2 2(8)]. C—H⋯π interactions also occur, leading to a chain along the b-axis direction. There is a rather weak π–π electron interaction between the pyrrazole and benzene rings, with a centroid–centroid distance of 3.765 (1) Å.

In the title compound, C 29 H 28 N 2 O 4 , the indoline ring system is essentially planar, with a maximum deviation of 0.027 (2) Å ; the carbonyl O atom lies 0.102 (1) Å out of the least-squares plane of the indole ring. The pyrrolidine ring adopts a Cenvelope conformation, with a C atom displaced by 0.643 (2) Å from the mean plane formed by the remaining ring atoms. The pyrrolidine ring makes a dihedral angle of 86.1 (8) with the indoline ring system. In the crystal, N-HÁ Á ÁO hydrogen bonds result in the formation of cyclic centrosymmetric dimers [R 2 2 (8)]. C-HÁ Á Á interactions also occur, leading to a chain along the b-axis direction. There is a rather weakelectron interaction between the pyrrazole and benzene rings, with a centroid-centroid distance of 3.765 (1) Å .

Experimental
Cg4 is the centroid of the C14-C19 ring.

Raghunathan and Devadasan Velmurugan Comment
Highly functionalized pyrrolidines have gained much interest in the past few years as they constitute main structural unit of many natural and synthetic pharmacologically active compounds (Waldmann, 1995). In continuation of our work on the crystal structure analysis of spiro-pyrrolidine derivatives (Narayanan et al., 2012), the crystal structure of the title compound has been carried out and the results are presented here.
The bond lengths and angles in the title molecule ( Fig. 1) are within normal ranges and comparable to those found in a related structure (Ganesh et al., 2012). The indoline ring system (C4-C11/N2) is essentially planar, with maximum deviation of 0.027 (2) Å for atom C5; O2 lies 0.102 (1) Å out of the leastsquares plane of the indole ring. The pyrrolidine ring (C1-C4/N1) adopts a C1-envelop conformation with C1 0.643 (2) Å displaced from the mean-plane formed by the remaining ring atoms. The pyrrolidine ring makes a dihedral angle of 86.1 (8)° with the indoline ring system. The dihedral angle between the mean-planes of the pyrrolidine ring and the benzene ring (C24-C29) is 64.1 (1)°.

Refinement
All H atoms were fixed geometrically and allowed to ride on their parent C atoms, with N-H = 0.86 Å and C-H distances in the range 0.93-0.98 Å with U iso (H) = 1.5U eq (methyl C) and 1.2U eq (non-methyl C/N).   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.