A triclinic polymorph of methyl (3R,3′S)-1′,1′′-dimethyl-2,2′′-dioxodispiro­[indoline-3,2′-pyrrolidine-3′,3′′-indoline]-4′-carboxyl­ate

G Ganesh; Panneer Selvam Yuvaraj; Chinthalapuri Divakara; Boreddy S R Reddy; A SubbiahPandi

doi:10.1107/S160053681204706X

. 2012 Nov 28;68(Pt 12):o3468–o3469. doi: 10.1107/S160053681204706X

A triclinic polymorph of methyl (3R,3′S)-1′,1′′-dimethyl-2,2′′-dioxodispiro[indoline-3,2′-pyrrolidine-3′,3′′-indoline]-4′-carboxylate

G Ganesh ^a, Panneer Selvam Yuvaraj ^b, Chinthalapuri Divakara ^b, Boreddy S R Reddy ^b, A SubbiahPandi ^c,^*

PMCID: PMC3589042 PMID: 23476278

Abstract

In the title compound, C₂₂H₂₁N₃O₄, the central pyrrolidine ring adopts a C-envelope conformation with a C atom 0.6593 (13) Å displaced from the mean plane formed by the remaining ring atoms. The indoline ring systems (r.m.s. devisations of 0.0356 and 0.0547 Å) are almost perpendicular to the mean plane of the pyrrolidine ring, making dihedral angles of 89.7 (6) and 82.5 (6)°. The acetate group attached to the pyrrolidine ring assumes an extended conformation. In the crystal,N—H⋯O and C—H⋯O hydrogen bonds connect adjacent molecules, forming an infinite tape extending along [1-1-1]. The crystal packing is further consolidated by strong π–π interactions with a centroid–centroid distance of 3.2585 (8) Å. The title compound is a polymorph of previously reported monoclinic structure [Ganesh et al. (2012 ▶). Acta Cryst. E68, o2902–o2903].

Related literature

For background literature and the previously reported polymorph, see: Ganesh et al. (2008). For a related structure, see: Wei et al. (2011 ▶).

Experimental

Crystal data

C₂₂H₂₁N₃O₄
M _r = 391.42
Triclinic,
a = 9.4418 (3) Å
b = 10.0132 (3) Å
c = 12.8861 (4) Å
α = 67.465 (2)°
β = 88.237 (2)°
γ = 62.842 (1)°
V = 985.68 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.25 × 0.22 × 0.19 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.978, T _max = 0.983
23829 measured reflections
8469 independent reflections
5108 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.051
wR(F ²) = 0.158
S = 1.08
8469 reflections
265 parameters
H-atom parameters constrained
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012) ▶; software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(23KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681204706X/pv2603sup1.cif

e-68-o3468-sup1.cif^{(23KB, cif)}

Click here for additional data file.^{(350.7KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681204706X/pv2603Isup2.hkl

e-68-o3468-Isup2.hkl^{(350.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3⋯O1ⁱ	0.86	2.10	2.9107 (12)	157
C15—H15B⋯O1ⁱⁱ	0.96	2.47	3.363 (2)	155

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the data collection. ASP thanks the University Grants Commission, India, for a Minor Research Project.

supplementary crystallographic information

Comment

We have recently reported the structure of the title compound in the monoclinic system (Ganesh et al., 2012). Here we report the structural details of its triclinic polymorph.

The bond lengths and angles in the title molecule (Fig. 1) are within normal ranges and comparable to those reported for its triclinic polymorph (Ganesh et al., 2012) and a closely related structure (Wei et al., 2011). The indoline ring systems (N1/C2-C9 and N3/C12/C16-C22) are individually planar (rmsd's 0.0356 and 0.0547 Å, respectively) and make dihedral angles of 89.69 (6) ° and 82.48 (6)° with respect to the mean plane of the pyrrolidine ring system (N2/C3/C10–C12). The pyrrolidine ring [N2/C3/C10-C12] adopts a C12-envelop conformation with C12 0.6593 (13) Å displaced from the mean-plane formed by the remaining ring atoms. The acetate group assumes an extended conformation (torsion angle C10–C14–O4–C15 = 176.3 (2) °).

The crystal structure is stabilized by intermolecular N3—H3···O1 and C15—H15B···O1 hydrogen bonds. There are strong π–π interactions with a centroid-centroid distance of 3.2585 (8) Å between Cg1 and Cg3 rings. {Cg1 and Cg3 are the centroids of the N1/C2-C5 and N3/C12/C16-C18 rings respectively}.

Experimental

A mixture of 1 eq of (E)-methyl 2-(1-methyl-2-oxoindolin-3-ylidene) acetate, 1 eq of isatin and 1.5 eq of sarcosine dissolved in acetonitrile was refluxed at 353 K for 8 h. Upon completion of the reaction as determined with the aid of TLC, the reaction mixture was extracted with ethyl acetate and water. The product was dried and purified by column chromatography using ethyl acetate and hexane (1:9) as an elutent to afford the title compound in pure form. (Yield = 90%). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.