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

Marx, A.; Chakkaravarthi, G.; Gobirajeshwaran, G.; Mohanakrishnan, A.K.; Manivannan, V.

doi:10.1107/S1600536808034156

organic compounds

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Volume 64| Part 11| November 2008| Page o2200

doi:10.1107/S1600536808034156

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

A. Marx,^a G. Chakkaravarthi,^b G. Gobirajeshwaran,^c A. K. Mohanakrishnan ^c and V. Manivannan ^a ^*

^aDepartment of Physics, Presidency College, Chennai 600 005, India, ^bDepartment of Physics, CPCL Polytechnic College, Chennai 600 068, India, and ^cDepartment of Organic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India
^*Correspondence e-mail: manivan_1999@yahoo.com

(Received 9 October 2008; accepted 19 October 2008; online 25 October 2008)

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, P 2₁ /c
a = 7.5511 (3) Å
b = 12.2476 (6) Å
c = 12.9449 (5) Å
β = 105.488 (2)°
V = 1153.71 (9) Å³
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[F² > 2σ(F²)] = 0.056
wR(F²) = 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

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) $[-x+2, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) -x+2, -y, -z+1. Cg1 is the centroid of the C1–C6 ring.

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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808034156/bq2100sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808034156/bq2100Isup2.hkl

checkCIF report

Comment top

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).

Related literature top

For biological activities of indole derivatives, see: Okabe & Adachi (1998); Schollmeyer et al. (1995). For related structures, see: Chakkaravarthi et al. (2007, 2008). Cg1 is the centroid of the C1–C6 ring.

Experimental top

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.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 (Bruker, 2004); data reduction: APEX2 (Bruker, 2004); 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 (Sheldrick, 2008).

Figures top

	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.

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

Crystal data top

C₁₃H₁₅NO₂	F(000) = 464
M_r = 217.26	D_x = 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 top

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

Refinement top

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(F_o²) + (0.0844P)² + 0.1542P] where P = (F_o² + 2F_c²)/3
3620 reflections	(Δ/σ)_max < 0.001
148 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₁₃H₁₅NO₂	V = 1153.71 (9) Å³
M_r = 217.26	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.5511 (3) Å	µ = 0.08 mm⁻¹
b = 12.2476 (6) Å	T = 295 K
c = 12.9449 (5) Å	0.25 × 0.20 × 0.20 mm
β = 105.488 (2)°

Data collection top

Bruker Kappa APEXII diffractometer	3620 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2068 reflections with I > 2σ(I)
T_min = 0.979, T_max = 0.983	R_int = 0.026
15440 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	0 restraints
wR(F²) = 0.184	H-atom parameters constrained
S = 1.03	Δρ_max = 0.21 e Å⁻³
3620 reflections	Δρ_min = −0.17 e Å⁻³
148 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
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 (Å²) top

	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, º) top

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, º) top

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.

Experimental details

Crystal data
Chemical formula	C₁₃H₁₅NO₂
M_r	217.26
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	295
a, b, c (Å)	7.5511 (3), 12.2476 (6), 12.9449 (5)
β (°)	105.488 (2)
V (Å³)	1153.71 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.25 × 0.20 × 0.20

Data collection
Diffractometer	Bruker Kappa APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.979, 0.983
No. of measured, independent and observed [I > 2σ(I)] reflections	15440, 3620, 2068
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.724

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.184, 1.03
No. of reflections	3620
No. of parameters	148
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.17

Computer programs: APEX2 (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

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.

Acknowledgements

The authors acknowledge the Sophisticated Analytical Instrument Facility, Indian Institute of Technology, Madras, for the data collection.

References

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