Crystal structure of 5-bromo-1-ethyl­indoline-2,3-dione

Yassine Kharbach; Amal Haoudi; Frédéric Capet; Ahmed Mazzah; Lahcen El Ammari

doi:10.1107/S2056989015023002

. 2015 Dec 6;71(Pt 12):o1024–o1025. doi: 10.1107/S2056989015023002

Crystal structure of 5-bromo-1-ethylindoline-2,3-dione

Yassine Kharbach ^a,^*, Amal Haoudi ^a, Frédéric Capet ^b, Ahmed Mazzah ^c, Lahcen El Ammari ^d

PMCID: PMC4719959 PMID: 26870478

Abstract

The title compound, C₁₀H₈BrNO₂, crystallizes with two independent molcules (A and B) in the asymmetric unit. In each molecule, the indoline ring system is almost planar, with the largest deviation from the mean plane being 0.016 (2) Å in molecule A and 0.040 (13) Å in molecule B. In each molecule, the ethyl group is nearly perpendicular to the indoline ring system with C—C—N—C torsion angles of −94.8 (3) and 93.0 (3)° in molecules A and B, respectively. In the crystal, the two molecules are inclined to each other, making a dihedral angle of 6.28 (8)°. In the molecular packing, the A and B molecules are linked by C—H⋯O hydrogen bonds, forming –A–B–A–B– chains along [01-1]. Parallel chains are linked via a weak slipped parallel π–π interaction [inter-centroid distance = 3.6107 (14) Å] and a short Br⋯O contact [3.183 (2) Å], forming a three-dimensional structure.

Keywords: crystal structure, indoline, C—H⋯O hydrogen bonds, slipped parallel π–π interaction, short Br⋯O interaction

Related literature

For biological activities of isatin derivatives, see: Samus et al. (2004 ▸); Sarangapani & Reddy (1994 ▸); Varma et al. (2004 ▸); Pandeya et al. (1999 ▸). For the use of isatin derivatives as reagents in organic synthesis and as raw materials for drug synthesis, see: Abele et al. (2003 ▸). For their use as corrosion inhibitors, see: Da Silva et al. (2013 ▸).

Experimental

Crystal data

C₁₀H₈BrNO₂
M _r = 254.08
Triclinic,
a = 9.5198 (3) Å
b = 10.0655 (3) Å
c = 11.2341 (3) Å
α = 70.9288 (16)°
β = 75.4109 (16)°
γ = 85.2199 (16)°
V = 984.58 (5) Å³
Z = 4
Mo Kα radiation
μ = 4.15 mm⁻¹
T = 296 K
0.50 × 0.27 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▸) T _min = 0.363, T _max = 0.746
40192 measured reflections
6275 independent reflections
4053 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.105
S = 1.02
6275 reflections
255 parameters
H-atom parameters constrained
Δρ_max = 0.66 e Å⁻³
Δρ_min = −0.47 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▸); cell refinement: SAINT (Bruker, 2009 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸) and Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: PLATON (Spek, 2009 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015023002/su5250sup1.cif

e-71-o1024-sup1.cif^{(1.1MB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015023002/su5250Isup2.hkl

e-71-o1024-Isup2.hkl^{(498.7KB, hkl)}

Click here for additional data file.^{(3.6KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015023002/su5250Isup3.cml

Click here for additional data file.^{(1.9MB, tif)}

. DOI: 10.1107/S2056989015023002/su5250fig1.tif

Molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Click here for additional data file.^{(1.9MB, tif)}

a . DOI: 10.1107/S2056989015023002/su5250fig2.tif

A view along the a axis of the crystal packing of the title compound. Hydrogen bonds (see Table 1) and other short interactions are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity.

CCDC reference: 1439717

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9A⋯O3ⁱ	0.97	2.58	3.351 (4)	136
C13—H13⋯O1ⁱⁱ	0.93	2.60	3.514 (3)	170
C19—H19B⋯O1ⁱⁱ	0.97	2.54	3.368 (3)	143

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

supplementary crystallographic information

S1. Synthesis and crystallization

To 5-bromo-1H-indole-2,3-dione (0.4 g, 1.76 mmol) in DMF (25 ml) was added 1-bromoethane (0.21 ml, 1.93 mmol), potassium carbonate (0.6 g, 4.4 mmol), and a catalytic amount of tetra-n-butylammonium bromide (0.1 g, 0.4 mmol). The mixture was stirred at room temperature for 48 h. The reaction was monitored by thin layer chromatography. On completion of the reaction the mixture was filtered and the solvent removed under vacuum. The title compound was obtained in 79% yield as red prismatic crystals (m.p. 409 K).

S2. Structural commentary

5-bromoisatin is an isatin derivative which has been reported to show a variety of biological activities, such as antibacterial, antimicrobial, antifungal and anti-HIV activities (Samus et al., 2004; Sarangapani & Reddy, 1994; Varma et al., 2004; Pandeya et al., 1999). It has been used as a versatile reagent in organic synthesis, to obtain heterocyclic compounds, and as a raw material for drug synthesis (Abele et al., 2003). Several isatin derivatives have been reported as being effective corrosion inhibitors for aluminium, copper and steel in different acid solution (Da Silva et al., 2013).

The title compound, Fig. 1, crystallizes with two independent molecules (A and B) in the asymmetric unit. In each molecule the indoline ring system is almost planar with the largest deviation from the mean plane being 0.016 (2) Å for atom C8 in molecule A, and 0.040 (13) Å for atom C18 in molecule B. In each molecule, the ethyl group is nearly perpendicular to the indoline ring system as indicated by the torsion angles of C10–C9–N1–C8 = −94.8 (3)° and C20–C19–N2–C18 = −92.9 (3)°.

In the crystal, the two molecules are inclined to each other with a dihedral angle of 6.28 (8)°. The A and B molecules are linked to one another by C—H···O hydrogen bonds, forming –A—B—A—B– chains along direction [011]; see Table 1 and Fig. 2. Parallel chains are linked via a weak parallel slipped π–π interaction [Cg1···Cg5ⁱ = 3.6107 (14) Å, Cg1 and Cg5 are the centroids of rings (N1/C3/C4/C7/C8) and (C11—C16), respectively, inter-planar distance = 3.4584 (9) Å, slippage = 1.262 Å; symmetry code: (i) x, y − 1, z] and a short Br1···O4ⁱⁱ contact [3.183 (2) Å; symmetry code: (ii) x − 1, y, z] forming a three-dimensional structure (Fig. 2).

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Crystal data, data collection and structure refinement details are summarized in Table 2. The H atoms were located in a difference Fourier map and treated as riding: C—H = 0.93–0.97 Å with U_iso(H) = 1.5U_eq(C-methyl) and 1.2U_eq(C) for other H atoms. The reflection (1 0 0) affected by the beam stop was removed during the final cycles of refinement.