[2-(1H-Indol-4-yl)eth­yl]dipropyl­amine

Wang, D.-C.; Pan, H.-Y.; Song, J.-S.; Wei, P.; Ou-yang, P.-K.

doi:10.1107/S1600536812015474

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 5| May 2012| Page o1502

doi:10.1107/S1600536812015474

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[2-(1H-Indol-4-yl)ethyl]dipropylamine

De-Cai Wang,^a ^* Hua-Yang Pan,^a Jun-Song Song,^a Ping Wei ^a and Ping-Kai Ou-yang ^a

^aState Key Laboratory of Materials-Oriented Chemical Engineering, School of Pharmaceutical Sciences, Nanjing University of Technology, Xinmofan Road No. 5 Nanjing, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: dc_wang@hotmail.com

(Received 19 March 2012; accepted 10 April 2012; online 21 April 2012)

In the title compound, C₁₆H₂₄N₂, the aliphatic amine substituent is rotated almost orthogonally [C—C—C—C torsion angle = 75.7 (3)°] out of the plane of the indole unit. The amine N atom has a pyramidal configuration deviating by 0.380 (3) Å from the plane of the adjacent C atoms. All of the aliphatic groups are in extended transoid conformations. In the crystal, molecules form chains along the a axis via N—H⋯N hydrogen bonds.

Related literature

For the synthesis and applications of the title compound, see: Srivastava et al. (1999 ).

Experimental

Crystal data

C₁₆H₂₄N₂
M_r = 244.37
Orthorhombic, P b c a
a = 12.1100 (9) Å
b = 15.5996 (12) Å
c = 16.0253 (12) Å
V = 3027.4 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.981, T_max = 0.994
2757 measured reflections
2757 independent reflections
1294 reflections with I > 2σ(I)
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.060
wR(F²) = 0.122
S = 1.00
2757 reflections
163 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.12 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N2ⁱ	0.86	2.10	2.945 (3)	166
Symmetry code: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ .

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812015474/ld2053sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812015474/ld2053Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812015474/ld2053Isup3.cml

checkCIF report

Comment top

The title compound is an important organic intermediate for the synthesis of 4-[2-(dipropylamino)ethyl]indol-2-one, an important compound for stimulating presynaptic dopamine autoreceptors in mammals (Srivastava et al., 1999). In the process of synthesis, we obtained the crystal of the intermediate and we report its crystal structure.

Related literature top

For the synthesis and applications of the title compound, see: Srivastava et al. (1999).

Experimental top

The title compound was synthesized according to the published procedure (Srivastava et al., 1999). A mixture of 4-[(2-amino)ethyl]indole (3.0 g, 18.72 mmol), 1-bromopropane (4.61 g, 37.44 mmol), K₂CO₃ (1 g, 7.25 mmol) in toluene (40 ml) was stirred at reflux temperature until the reaction completion is checked by thin layer silica gel (60–80 mesh) plates. When the mixture reached room temperature, it was filtered and the filtrate was poured in water and extracted with chloroform. The combined extract is washed with 10% brine solution, dried over Na₂S0₄ and concentrated to afford the crude product, which was filtered through column. The obtained material was distilled to afford the pure product 3.62 g with a 79% yield. The product (0.3 g) was crystallized from methanol (15 ml) at room temperature to give colorless crystals that were used for data collection.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The structure of the title compound, showing the atomic numbering scheme. Non-H atoms are shown with 30% probability displacement ellipsoids.

[2-(1H-Indol-4-yl)ethyl]dipropylamine top

Crystal data top

C₁₆H₂₄N₂	F(000) = 1072
M_r = 244.37	D_x = 1.072 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 25 reflections
a = 12.1100 (9) Å	θ = 9–13°
b = 15.5996 (12) Å	µ = 0.06 mm⁻¹
c = 16.0253 (12) Å	T = 293 K
V = 3027.4 (4) Å³	Block, white
Z = 8	0.30 × 0.20 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1294 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.000
Graphite monochromator	θ_max = 25.4°, θ_min = 2.5°
ω/2θ scans	h = 0→14
Absorption correction: ψ scan (North et al., 1968)	k = 0→18
T_min = 0.981, T_max = 0.994	l = 0→19
2757 measured reflections	3 standard reflections every 200 reflections
2757 independent reflections	intensity decay: 1%

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)] = 0.060	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.122	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.039P)²] where P = (F_o² + 2F_c²)/3
2757 reflections	(Δ/σ)_max < 0.001
163 parameters	Δρ_max = 0.22 e Å⁻³
2 restraints	Δρ_min = −0.12 e Å⁻³

Crystal data top

C₁₆H₂₄N₂	V = 3027.4 (4) Å³
M_r = 244.37	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 12.1100 (9) Å	µ = 0.06 mm⁻¹
b = 15.5996 (12) Å	T = 293 K
c = 16.0253 (12) Å	0.30 × 0.20 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1294 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.000
T_min = 0.981, T_max = 0.994	3 standard reflections every 200 reflections
2757 measured reflections	intensity decay: 1%
2757 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.060	2 restraints
wR(F²) = 0.122	H-atom parameters constrained
S = 1.00	Δρ_max = 0.22 e Å⁻³
2757 reflections	Δρ_min = −0.12 e Å⁻³
163 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
C1	0.69898 (17)	0.17493 (14)	0.51171 (13)	0.0529 (6)
N1	0.80610 (17)	0.26448 (12)	0.58576 (12)	0.0672 (6)
H1A	0.8600	0.2852	0.6144	0.081*
N2	0.46143 (14)	0.14524 (11)	0.30351 (11)	0.0570 (5)
C2	0.64447 (19)	0.25584 (16)	0.51942 (15)	0.0661 (7)
H2A	0.5756	0.2705	0.4981	0.079*
C3	0.7130 (2)	0.30703 (15)	0.56402 (16)	0.0719 (7)
H3A	0.6980	0.3638	0.5778	0.086*
C4	0.79988 (18)	0.18272 (15)	0.55438 (14)	0.0572 (6)
C5	0.87487 (19)	0.11580 (17)	0.55988 (17)	0.0738 (8)
H5A	0.9418	0.1220	0.5877	0.089*
C6	0.8458 (2)	0.04041 (16)	0.52256 (17)	0.0809 (8)
H6A	0.8942	−0.0058	0.5252	0.097*
C7	0.7459 (2)	0.03062 (15)	0.48071 (16)	0.0736 (7)
H7A	0.7294	−0.0219	0.4563	0.088*
C8	0.67057 (17)	0.09681 (14)	0.47445 (13)	0.0562 (6)
C9	0.56340 (17)	0.08773 (14)	0.42753 (14)	0.0611 (6)
H9A	0.5043	0.1133	0.4599	0.073*
H9B	0.5467	0.0274	0.4204	0.073*
C10	0.56870 (18)	0.13063 (14)	0.34234 (13)	0.0608 (6)
H10A	0.6061	0.1853	0.3482	0.073*
H10B	0.6128	0.0952	0.3054	0.073*
C11	0.3925 (2)	0.06598 (15)	0.29295 (17)	0.0822 (8)
H11A	0.3830	0.0401	0.3475	0.099*
H11B	0.3200	0.0835	0.2737	0.099*
C12	0.4330 (2)	0.00010 (17)	0.2365 (2)	0.1074 (10)
H12A	0.5053	−0.0195	0.2543	0.129*
H12B	0.4396	0.0231	0.1804	0.129*
C13	0.3492 (3)	−0.07629 (16)	0.2374 (2)	0.1313 (13)
H13A	0.3739	−0.1201	0.1996	0.197*
H13B	0.2777	−0.0562	0.2203	0.197*
H13C	0.3445	−0.0994	0.2928	0.197*
C14	0.4724 (2)	0.19861 (16)	0.22911 (15)	0.0805 (8)
H14A	0.5079	0.1647	0.1860	0.097*
H14B	0.5215	0.2459	0.2423	0.097*
C15	0.3695 (2)	0.2346 (2)	0.1942 (2)	0.1199 (11)
H15A	0.3244	0.2555	0.2398	0.144*
H15B	0.3289	0.1888	0.1670	0.144*
C16	0.3850 (2)	0.30558 (17)	0.13303 (18)	0.1030 (10)
H16A	0.3141	0.3258	0.1146	0.155*
H16B	0.4262	0.2850	0.0860	0.155*
H16C	0.4245	0.3517	0.1591	0.155*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0514 (12)	0.0586 (14)	0.0488 (14)	−0.0011 (12)	−0.0021 (12)	0.0050 (12)
N1	0.0656 (13)	0.0724 (14)	0.0634 (14)	−0.0148 (11)	−0.0121 (11)	0.0002 (11)
N2	0.0528 (11)	0.0663 (11)	0.0520 (12)	0.0045 (9)	−0.0036 (10)	0.0009 (10)
C2	0.0560 (14)	0.0747 (16)	0.0675 (18)	0.0034 (13)	−0.0038 (14)	0.0044 (15)
C3	0.0754 (17)	0.0649 (16)	0.0755 (19)	0.0011 (15)	−0.0004 (15)	−0.0017 (15)
C4	0.0540 (14)	0.0626 (16)	0.0549 (15)	−0.0124 (13)	−0.0051 (13)	0.0077 (13)
C5	0.0543 (15)	0.0775 (18)	0.090 (2)	−0.0078 (14)	−0.0185 (14)	0.0184 (16)
C6	0.0620 (17)	0.0649 (17)	0.116 (2)	0.0074 (13)	−0.0148 (17)	0.0109 (17)
C7	0.0730 (17)	0.0570 (15)	0.091 (2)	−0.0010 (14)	−0.0053 (16)	−0.0016 (14)
C8	0.0528 (14)	0.0616 (15)	0.0542 (15)	−0.0063 (12)	−0.0022 (12)	0.0056 (13)
C9	0.0570 (14)	0.0686 (15)	0.0575 (15)	−0.0113 (12)	−0.0067 (13)	0.0029 (13)
C10	0.0523 (14)	0.0735 (16)	0.0567 (16)	−0.0031 (12)	0.0003 (13)	0.0031 (13)
C11	0.0859 (19)	0.0750 (16)	0.086 (2)	−0.0045 (12)	−0.0250 (16)	−0.0099 (16)
C12	0.110 (2)	0.098 (2)	0.115 (3)	−0.0031 (16)	−0.004 (2)	−0.015 (2)
C13	0.142 (3)	0.086 (2)	0.166 (3)	−0.0158 (17)	−0.045 (2)	−0.032 (2)
C14	0.0766 (18)	0.099 (2)	0.065 (2)	0.0077 (15)	−0.0086 (15)	0.0167 (16)
C15	0.090 (2)	0.170 (3)	0.100 (3)	0.013 (2)	−0.010 (2)	0.046 (2)
C16	0.125 (2)	0.101 (2)	0.083 (2)	0.0286 (19)	−0.0048 (19)	0.0154 (19)

Geometric parameters (Å, º) top

C1—C8	1.400 (3)	C9—H9B	0.9700
C1—C4	1.405 (3)	C10—H10A	0.9700
C1—C2	1.430 (3)	C10—H10B	0.9700
N1—C3	1.354 (3)	C11—C12	1.455 (3)
N1—C4	1.373 (2)	C11—H11A	0.9700
N1—H1A	0.8600	C11—H11B	0.9700
N2—C10	1.458 (2)	C12—C13	1.566 (3)
N2—C14	1.460 (3)	C12—H12A	0.9700
N2—C11	1.501 (2)	C12—H12B	0.9700
C2—C3	1.355 (3)	C13—H13A	0.9600
C2—H2A	0.9300	C13—H13B	0.9600
C3—H3A	0.9300	C13—H13C	0.9600
C4—C5	1.386 (3)	C14—C15	1.477 (3)
C5—C6	1.366 (3)	C14—H14A	0.9700
C5—H5A	0.9300	C14—H14B	0.9700
C6—C7	1.391 (3)	C15—C16	1.490 (3)
C6—H6A	0.9300	C15—H15A	0.9700
C7—C8	1.381 (3)	C15—H15B	0.9700
C7—H7A	0.9300	C16—H16A	0.9600
C8—C9	1.507 (3)	C16—H16B	0.9600
C9—C10	1.522 (3)	C16—H16C	0.9600
C9—H9A	0.9700

C8—C1—C4	119.8 (2)	N2—C10—H10B	108.6
C8—C1—C2	133.8 (2)	C9—C10—H10B	108.6
C4—C1—C2	106.4 (2)	H10A—C10—H10B	107.6
C3—N1—C4	108.38 (19)	C12—C11—N2	117.7 (2)
C3—N1—H1A	125.8	C12—C11—H11A	107.9
C4—N1—H1A	125.8	N2—C11—H11A	107.9
C10—N2—C14	110.90 (17)	C12—C11—H11B	107.9
C10—N2—C11	114.50 (17)	N2—C11—H11B	107.9
C14—N2—C11	115.34 (19)	H11A—C11—H11B	107.2
C3—C2—C1	106.4 (2)	C11—C12—C13	108.2 (2)
C3—C2—H2A	126.8	C11—C12—H12A	110.0
C1—C2—H2A	126.8	C13—C12—H12A	110.0
N1—C3—C2	110.9 (2)	C11—C12—H12B	110.0
N1—C3—H3A	124.6	C13—C12—H12B	110.0
C2—C3—H3A	124.6	H12A—C12—H12B	108.4
N1—C4—C5	129.8 (2)	C12—C13—H13A	109.5
N1—C4—C1	107.8 (2)	C12—C13—H13B	109.5
C5—C4—C1	122.4 (2)	H13A—C13—H13B	109.5
C6—C5—C4	116.8 (2)	C12—C13—H13C	109.5
C6—C5—H5A	121.6	H13A—C13—H13C	109.5
C4—C5—H5A	121.6	H13B—C13—H13C	109.5
C5—C6—C7	122.0 (2)	N2—C14—C15	116.7 (2)
C5—C6—H6A	119.0	N2—C14—H14A	108.1
C7—C6—H6A	119.0	C15—C14—H14A	108.1
C8—C7—C6	121.8 (2)	N2—C14—H14B	108.1
C8—C7—H7A	119.1	C15—C14—H14B	108.1
C6—C7—H7A	119.1	H14A—C14—H14B	107.3
C7—C8—C1	117.2 (2)	C14—C15—C16	115.2 (3)
C7—C8—C9	122.3 (2)	C14—C15—H15A	108.5
C1—C8—C9	120.4 (2)	C16—C15—H15A	108.5
C8—C9—C10	111.72 (17)	C14—C15—H15B	108.5
C8—C9—H9A	109.3	C16—C15—H15B	108.5
C10—C9—H9A	109.3	H15A—C15—H15B	107.5
C8—C9—H9B	109.3	C15—C16—H16A	109.5
C10—C9—H9B	109.3	C15—C16—H16B	109.5
H9A—C9—H9B	107.9	H16A—C16—H16B	109.5
N2—C10—C9	114.46 (18)	C15—C16—H16C	109.5
N2—C10—H10A	108.6	H16A—C16—H16C	109.5
C9—C10—H10A	108.6	H16B—C16—H16C	109.5

C8—C1—C2—C3	178.9 (2)	C4—C1—C8—C7	−1.0 (3)
C4—C1—C2—C3	0.6 (2)	C2—C1—C8—C7	−179.2 (2)
C4—N1—C3—C2	0.4 (3)	C4—C1—C8—C9	−179.20 (19)
C1—C2—C3—N1	−0.6 (3)	C2—C1—C8—C9	2.7 (4)
C3—N1—C4—C5	179.7 (2)	C7—C8—C9—C10	−102.4 (2)
C3—N1—C4—C1	0.0 (2)	C1—C8—C9—C10	75.7 (3)
C8—C1—C4—N1	−178.98 (19)	C14—N2—C10—C9	170.78 (18)
C2—C1—C4—N1	−0.4 (2)	C11—N2—C10—C9	−56.6 (3)
C8—C1—C4—C5	1.4 (3)	C8—C9—C10—N2	−163.88 (18)
C2—C1—C4—C5	180.0 (2)	C10—N2—C11—C12	−65.2 (3)
N1—C4—C5—C6	179.5 (2)	C14—N2—C11—C12	65.3 (3)
C1—C4—C5—C6	−0.9 (4)	N2—C11—C12—C13	178.8 (2)
C4—C5—C6—C7	0.1 (4)	C10—N2—C14—C15	−166.8 (2)
C5—C6—C7—C8	0.1 (4)	C11—N2—C14—C15	61.0 (3)
C6—C7—C8—C1	0.3 (4)	N2—C14—C15—C16	164.9 (2)
C6—C7—C8—C9	178.5 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N2ⁱ	0.86	2.10	2.945 (3)	166

Symmetry code: (i) x+1/2, −y+1/2, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₆H₂₄N₂
M_r	244.37
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	293
a, b, c (Å)	12.1100 (9), 15.5996 (12), 16.0253 (12)
V (Å³)	3027.4 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.06
Crystal size (mm)	0.30 × 0.20 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.981, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	2757, 2757, 1294
R_int	0.000
(sin θ/λ)_max (Å⁻¹)	0.602

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.060, 0.122, 1.00
No. of reflections	2757
No. of parameters	163
No. of restraints	2
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.12

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N2ⁱ	0.86	2.10	2.945 (3)	166.0

Symmetry code: (i) x+1/2, −y+1/2, −z+1.

Acknowledgements

The work was supported by the center of Testing and Analysis, Nanjing University.

References

Enraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius. Delft, The Netherlands. Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Srivastava, S. K., Chauhan, P. M. S. & Bhaduri, A. P. (1999). Synth. Commun. 29, 2085–2091. Web of Science CrossRef CAS Google Scholar