Ethyl 1,3-dimethyl-1H-indole-2-carboxyl­ate

Abstract

In the title compound, C₁₃H₁₅NO₂, the plane of the indole ring forms a dihedral angle of 5.26 (6)° with the ester group and the ethyl side-chain C atoms. The crystal packing is stabilized by weak inter­molecular C—H⋯O and C—H⋯π inter­actions.

Related literature

For biological activities of indole derivatives, see: Okabe & Adachi (1998 ▶); Schollmeyer et al. (1995 ▶). For related structures, see: Chakkaravarthi et al. (2007 ▶, 2008 ▶).

Experimental

Crystal data

• C₁₃H₁₅NO₂

• M _r = 217.26

• Monoclinic,

• a = 7.5511 (3) Å

• b = 12.2476 (6) Å

• c = 12.9449 (5) Å

• β = 105.488 (2)°

• V = 1153.71 (9) ų

• Z = 4

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 295 (2) K

• 0.25 × 0.20 × 0.20 mm

Data collection

• Bruker Kappa APEXII diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.979, T _max = 0.983

• 15440 measured reflections

• 3620 independent reflections

• 2068 reflections with I > 2σ(I)

• R _int = 0.026

Refinement

• R[F ² > 2σ(F ²)] = 0.056

• wR(F ²) = 0.184

• S = 1.03

• 3620 reflections

• 148 parameters

• H-atom parameters constrained

• Δρ_max = 0.21 e Å⁻³

• Δρ_min = −0.17 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT; data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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
C2—H2⋯O1i	0.93	2.53	3.401 (2)	156
C12—H12A⋯Cg1ii	0.97	2.76	3.646 (2)	152

Symmetry codes: (i) ; (ii) . Cg1 is the centroid of the C1–C6 ring.

supplementary crystallographic information

Comment

The indole derivatives are found to possess antibacterial (Okabe and Adachi, 1998) and antitumour activities (Schollmeyer et al., 1995). In continuation to our studies in indole derivatives, we determine the crystal structure of the title compound (I). The geometric parameters of the molecule of (I) (Fig. 1) agree well with the reported structures (Chakkaravarthi et al., 2007; Chakkaravarthi et al., 2008).

The five- (N1/C1/C6/C7/C8) and six- (C1—C6) membered rings in the indane group are almost planar, with a dihedral angle of 1.67 (6)° between these rings. The plane of indole ring forms a dihedral angle of 5.26 (6)° with the ester group. The molecular packing is stabilized by weak intramolecular C—H···O interaction and the crystal packing of (I) is stabilized by weak intermolecular C—H···O and C—H···π interactions (Table 1) (Fig. 2).

Experimental

To a stirred suspension of NaH (0.6 mmol, hexane washed) in THF (2 ml), a solution of 2-carbethoxy-3-methyl indole (0.5 mmol) in THF (2 ml) was added and stirred for 30 minutes at room temperature. To the reaction mixture, a solution of Iodomethane (0.6 mmol) was added and stirring was continued for further 6 hr. After the indole was consumed (monitored by TLC), the reaction mixture was quenched with cold dil HCl (25 ml), extracted with ethyl acetate (2 x 10 ml) and dried (Na₂SO₄). Removal of solvent followed by crystalization (hexane) afforded as yellow crystal.

Refinement

H atoms were positioned geometrically and refined using riding model with C—H = 0.93 Å and U_iso(H) = 1.2Ueq(C) for aromatic H atoms, C—H = 0.97 Å and U_iso(H) = 1.2Ueq(C) for CH2 and C—H = 0.96 Å and U_iso(H) = 1.5Ueq(C) for methyl H atoms.

Figures

Fig. 1.

The molecular structure of (I), with atom labeling scheme. Displacement ellipsoids are drawn at 50% probability level.

Fig. 2.

The crystal structure of (I), viewed down the a face. For the sake of clarity, H atoms not involved in interaction have been omitted.

Crystal data

C13H15NO2	F(000) = 464
Mr = 217.26	Dx = 1.251 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4312 reflections
a = 7.5511 (3) Å	θ = 2.3–24.1°
b = 12.2476 (6) Å	µ = 0.08 mm−1
c = 12.9449 (5) Å	T = 295 K
β = 105.488 (2)°	Block, yellow
V = 1153.71 (9) Å3	0.25 × 0.20 × 0.20 mm
Z = 4

Data collection

Bruker Kappa APEXII diffractometer	3620 independent reflections
Radiation source: fine-focus sealed tube	2068 reflections with I > 2σ(I)
graphite	Rint = 0.026
ω and φ scans	θmax = 31.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.979, Tmax = 0.983	k = −17→17
15440 measured reflections	l = −18→18

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.184	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.0844P)2 + 0.1542P] where P = (Fo2 + 2Fc2)/3
3620 reflections	(Δ/σ)max < 0.001
148 parameters	Δρmax = 0.21 e Å−3
0 restraints	Δρmin = −0.17 e Å−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7616 (2)	−0.19859 (13)	0.57067 (13)	0.0527 (4)
C2	0.7747 (2)	−0.30504 (16)	0.61130 (15)	0.0653 (5)
H2	0.8324	−0.3194	0.6829	0.078*
C3	0.7003 (3)	−0.38637 (16)	0.54252 (18)	0.0750 (5)
H3	0.7075	−0.4577	0.5679	0.090*
C4	0.6132 (3)	−0.36648 (16)	0.43493 (18)	0.0738 (5)
H4	0.5646	−0.4246	0.3901	0.089*
C5	0.5983 (2)	−0.26368 (16)	0.39465 (14)	0.0655 (4)
H5	0.5386	−0.2510	0.3230	0.079*
C6	0.67448 (19)	−0.17669 (13)	0.46276 (12)	0.0525 (4)
C7	0.68784 (19)	−0.06336 (13)	0.44615 (11)	0.0501 (4)
C8	0.78272 (19)	−0.01966 (13)	0.54312 (11)	0.0512 (4)
C9	0.9305 (3)	−0.09425 (17)	0.73226 (14)	0.0757 (5)
H9A	0.9384	−0.1651	0.7650	0.114*
H9B	0.8689	−0.0449	0.7687	0.114*
H9C	1.0519	−0.0675	0.7371	0.114*
C10	0.6076 (2)	−0.00822 (15)	0.34166 (13)	0.0670 (5)
H10A	0.5464	0.0575	0.3534	0.100*
H10B	0.5209	−0.0561	0.2955	0.100*
H10C	0.7038	0.0095	0.3088	0.100*
C11	0.8333 (2)	0.09395 (14)	0.57069 (13)	0.0559 (4)
C12	0.8335 (2)	0.27250 (13)	0.50367 (14)	0.0644 (4)
H12A	0.9652	0.2837	0.5286	0.077*
H12B	0.7771	0.3007	0.5573	0.077*
C13	0.7583 (3)	0.32875 (18)	0.40024 (17)	0.0805 (6)
H13A	0.8079	0.2962	0.3465	0.121*
H13B	0.7913	0.4046	0.4077	0.121*
H13C	0.6269	0.3219	0.3793	0.121*
N1	0.82742 (18)	−0.10221 (11)	0.61980 (10)	0.0568 (4)
O1	0.9033 (2)	0.12730 (12)	0.65918 (10)	0.0943 (5)
O2	0.79272 (16)	0.15785 (9)	0.48555 (9)	0.0632 (3)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0489 (7)	0.0561 (9)	0.0535 (9)	0.0029 (6)	0.0146 (6)	0.0022 (7)
C2	0.0636 (9)	0.0662 (11)	0.0666 (11)	0.0026 (8)	0.0182 (8)	0.0136 (9)
C3	0.0774 (12)	0.0564 (11)	0.0939 (15)	−0.0017 (9)	0.0278 (11)	0.0091 (10)
C4	0.0742 (11)	0.0606 (11)	0.0849 (14)	−0.0079 (9)	0.0183 (10)	−0.0079 (10)
C5	0.0627 (9)	0.0696 (11)	0.0595 (10)	−0.0025 (8)	0.0081 (7)	−0.0072 (9)
C6	0.0476 (7)	0.0574 (9)	0.0519 (8)	0.0043 (6)	0.0122 (6)	0.0002 (7)
C7	0.0499 (7)	0.0552 (9)	0.0439 (8)	0.0047 (6)	0.0104 (6)	−0.0002 (6)
C8	0.0529 (8)	0.0556 (9)	0.0459 (8)	0.0041 (6)	0.0144 (6)	0.0012 (7)
C9	0.0883 (13)	0.0815 (13)	0.0488 (9)	0.0011 (10)	0.0035 (9)	0.0088 (9)
C10	0.0770 (11)	0.0675 (11)	0.0492 (9)	0.0038 (9)	0.0043 (8)	0.0050 (8)
C11	0.0624 (9)	0.0597 (10)	0.0462 (8)	0.0004 (7)	0.0155 (7)	−0.0025 (7)
C12	0.0722 (10)	0.0549 (10)	0.0682 (11)	0.0016 (8)	0.0226 (8)	−0.0044 (8)
C13	0.0902 (13)	0.0688 (12)	0.0804 (13)	0.0093 (10)	0.0189 (11)	0.0097 (10)
N1	0.0588 (7)	0.0631 (9)	0.0467 (7)	0.0022 (6)	0.0109 (6)	0.0036 (6)
O1	0.1481 (14)	0.0728 (9)	0.0498 (7)	−0.0162 (9)	0.0050 (8)	−0.0092 (6)
O2	0.0805 (8)	0.0518 (7)	0.0536 (7)	−0.0007 (5)	0.0113 (6)	−0.0014 (5)

Geometric parameters (Å, °)

C1—N1	1.370 (2)	C9—N1	1.459 (2)
C1—C2	1.400 (2)	C9—H9A	0.9600
C1—C6	1.402 (2)	C9—H9B	0.9600
C2—C3	1.354 (3)	C9—H9C	0.9600
C2—H2	0.9300	C10—H10A	0.9600
C3—C4	1.394 (3)	C10—H10B	0.9600
C3—H3	0.9300	C10—H10C	0.9600
C4—C5	1.356 (3)	C11—O1	1.198 (2)
C4—H4	0.9300	C11—O2	1.319 (2)
C5—C6	1.404 (2)	C12—O2	1.443 (2)
C5—H5	0.9300	C12—C13	1.478 (3)
C6—C7	1.412 (2)	C12—H12A	0.9700
C7—C8	1.377 (2)	C12—H12B	0.9700
C7—C10	1.488 (2)	C13—H13A	0.9600
C8—N1	1.394 (2)	C13—H13B	0.9600
C8—C11	1.462 (2)	C13—H13C	0.9600
N1—C1—C2	130.38 (16)	H9A—C9—H9C	109.5
N1—C1—C6	108.26 (14)	H9B—C9—H9C	109.5
C2—C1—C6	121.33 (16)	C7—C10—H10A	109.5
C3—C2—C1	117.57 (17)	C7—C10—H10B	109.5
C3—C2—H2	121.2	H10A—C10—H10B	109.5
C1—C2—H2	121.2	C7—C10—H10C	109.5
C2—C3—C4	122.06 (18)	H10A—C10—H10C	109.5
C2—C3—H3	119.0	H10B—C10—H10C	109.5
C4—C3—H3	119.0	O1—C11—O2	122.77 (16)
C5—C4—C3	121.00 (18)	O1—C11—C8	125.30 (16)
C5—C4—H4	119.5	O2—C11—C8	111.93 (14)
C3—C4—H4	119.5	O2—C12—C13	107.02 (15)
C4—C5—C6	119.02 (17)	O2—C12—H12A	110.3
C4—C5—H5	120.5	C13—C12—H12A	110.3
C6—C5—H5	120.5	O2—C12—H12B	110.3
C1—C6—C5	119.01 (15)	C13—C12—H12B	110.3
C1—C6—C7	107.83 (14)	H12A—C12—H12B	108.6
C5—C6—C7	133.16 (15)	C12—C13—H13A	109.5
C8—C7—C6	106.51 (13)	C12—C13—H13B	109.5
C8—C7—C10	129.70 (16)	H13A—C13—H13B	109.5
C6—C7—C10	123.78 (14)	C12—C13—H13C	109.5
C7—C8—N1	109.60 (14)	H13A—C13—H13C	109.5
C7—C8—C11	129.14 (14)	H13B—C13—H13C	109.5
N1—C8—C11	121.25 (14)	C1—N1—C8	107.79 (13)
N1—C9—H9A	109.5	C1—N1—C9	123.47 (14)
N1—C9—H9B	109.5	C8—N1—C9	128.70 (15)
H9A—C9—H9B	109.5	C11—O2—C12	116.72 (13)
N1—C9—H9C	109.5
N1—C1—C2—C3	−177.99 (16)	C6—C7—C8—C11	−179.58 (14)
C6—C1—C2—C3	0.1 (2)	C10—C7—C8—C11	−0.7 (3)
C1—C2—C3—C4	0.0 (3)	C7—C8—C11—O1	173.58 (17)
C2—C3—C4—C5	−0.5 (3)	N1—C8—C11—O1	−5.4 (3)
C3—C4—C5—C6	0.9 (3)	C7—C8—C11—O2	−6.4 (2)
N1—C1—C6—C5	178.77 (13)	N1—C8—C11—O2	174.65 (12)
C2—C1—C6—C5	0.3 (2)	C2—C1—N1—C8	178.04 (15)
N1—C1—C6—C7	−0.08 (16)	C6—C1—N1—C8	−0.24 (16)
C2—C1—C6—C7	−178.54 (14)	C2—C1—N1—C9	−0.1 (3)
C4—C5—C6—C1	−0.8 (2)	C6—C1—N1—C9	−178.40 (14)
C4—C5—C6—C7	177.72 (16)	C7—C8—N1—C1	0.48 (16)
C1—C6—C7—C8	0.37 (16)	C11—C8—N1—C1	179.62 (13)
C5—C6—C7—C8	−178.25 (16)	C7—C8—N1—C9	178.52 (15)
C1—C6—C7—C10	−178.61 (14)	C11—C8—N1—C9	−2.3 (2)
C5—C6—C7—C10	2.8 (3)	O1—C11—O2—C12	−1.2 (2)
C6—C7—C8—N1	−0.52 (15)	C8—C11—O2—C12	178.80 (13)
C10—C7—C8—N1	178.38 (15)	C13—C12—O2—C11	−173.84 (14)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···O2	0.96	2.49	2.858 (2)	103
C2—H2···O1i	0.93	2.53	3.401 (2)	156
C12—H12A···Cg1ii	0.97	2.76	3.646 (2)	152

Symmetry codes: (i) −x+2, y−1/2, −z+3/2; (ii) −x+2, −y, −z+1.