1-(2-Amino-4,5-di­methyl­phen­yl)ethanone

Bosch, E.; Jeffries, L.

doi:10.1107/S2414314618003139

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 3| Part 2| February 2018| x180313

https://doi.org/10.1107/S2414314618003139

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1-(2-Amino-4,5-dimethylphenyl)ethanone

Eric Bosch ^a ^* and Laura Jeffries ^a

^aDepartment of Chemistrry, Missouri State University, 901 South National Avenue, Springfield, MO 65804, USA
^*Correspondence e-mail: ericbosch@missouristate.edu

Edited by J. Simpson, University of Otago, New Zealand (Received 21 February 2018; accepted 22 February 2018; online 28 February 2018)

The molecule of the title compound, C₁₀H₁₃NO, also referred to as 2-amino-4,5-dimethylacetophenone, lies on a crystallographic mirror plane with four molecules in the orthorhombic unit cell and features an intramolecular N—H⋯O hydrogen bond. In the crystal, the molecules are linked by N—H⋯O hydrogen bonds, forming ribbons along the a axis that pack to form sheets lying in the (010) plane.

Keywords: crystal structure; 2-aminoacetophenone; hydrogen bonding.

CCDC reference: 1825318

Structure description

The synthesis of 2-aminoacetophenone was accomplished in a one-pot reduction and hydration of 2-nitrophenacetylene with a variety of reagents generally used for the reduction of nitrobenzenes (Bosch & Jeffries, 2001 ). The asymmetric unit of the title compound comprises a single molecule that lies on a mirror plane with hydrogen atoms of the three methyl groups disordered over two positions. An intramolecular N1—H1N⋯O1 hydrogen bond (Fig. 1 and Table 1) supports the planar structure. A search of the Cambridge Structural Database (CSD, Version 5.39, November 2017, Groom et al., 2016 ) using Conquest (Bruno et al., 2002 ) for neutral uncomplexed molecules, including the 2-aminoacetophenone framework, yielded 99 hits. CSD entries not including atomic coordinates for H atoms were excluded. In 96 of these structures, an intramolecular N—H⋯O hydrogen bond was observed.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O1	0.89 (2)	1.96 (2)	2.6603 (19)	135 (2)
N1—H2N⋯O1ⁱ	0.86 (2)	2.09 (2)	2.9478 (18)	170 (2)
Symmetry code: (i) $[x+{\script{1\over 2}}, y, -z+{\script{1\over 2}}]$ .

Figure 1
The asymmetric unit of the title compound, showing the atom-numbering scheme. Displacement ellipsoids of non-H atoms are drawn at the 50% probability level and H atoms are shown as circles of arbitrary size. An intramolecular hydrogen bond is shown as a dashed line.

In the crystal, ribbons form along the a-axis direction through N1—H2N⋯O1 hydrogen bonds. Adjacent ribbons pack to form sheets lying in the (010) plane (Fig. 2). These sheets stack parallel to (101). There are possible extremely weak offset π–π stacking interactions (Fig. 3), with a centroid-to-centroid distance between the stacked benzene rings of 5.1075 (8) Å and with a slippage of 3.768 Å. In addition, the closest contact between stacked molecules is between the acetophenone methyl group and the centroid of the benzene ring, with a C8⋯Cg1 distance of 3.4531 (3) Å, suggesting that C8—H8⋯Cg1 contacts may also consolidate the stacking interaction, Cg1 is the centroid of the C1–C6 benzene ring.

Figure 2
A view of a sheet comprising side-by-side packing of one-dimensional hydrogen-bonded ribbons of the title compound. Hydrogen bonds are shown as a dashed lines.

Figure 3
View along the a axis of the offset π-stacked planes shown in Fig. 2

Synthesis and crystallization

The title compound was synthesized by a one-pot hydration and reduction of 1-ethynyl-4,5-dimethyl-2-nitrobenzene with Fe/HCl, SnCl₂ or nickel boride and the isolation and characterization have been reported previously (Bosch & Jeffries, 2001). Crystals suitable for X-ray data collection were obtained by slow evaporation of a dichloromethane solution.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₀H₁₃NO
M_r	163.21
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	173
a, b, c (Å)	10.4838 (7), 6.8965 (5), 12.8538 (9)
V (Å³)	929.35 (11)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.08
Crystal size (mm)	0.33 × 0.32 × 0.21

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2014 )
T_min, T_max	0.954, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	11353, 1115, 883
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.641

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.040, 0.116, 1.09
No. of reflections	1115
No. of parameters	80
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.19
Computer programs: SMART and SAINT (Bruker 2014), SHELXT2014 (Sheldrick, 2015a ), SHELXL2017 (Sheldrick, 2015b ) and X-SEED (Barbour, 2001 ).

Structural data

CCDC reference: 1825318

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314618003139/sj4164sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618003139/sj4164Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314618003139/sj4164Isup3.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2414314618003139/sj4164Isup4.cml

checkCIF report

Computing details top

Data collection: SMART (Bruker 2014); cell refinement: SMART (Bruker 2014); data reduction: SAINT (Bruker 2014); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: X-SEED (Barbour, 2001).

1-(2-Amino-4,5-dimethylphenyl)ethanone top

Crystal data top

C₁₀H₁₃NO	D_x = 1.167 Mg m⁻³
M_r = 163.21	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 2665 reflections
a = 10.4838 (7) Å	θ = 2.5–26.4°
b = 6.8965 (5) Å	µ = 0.08 mm⁻¹
c = 12.8538 (9) Å	T = 173 K
V = 929.35 (11) Å³	Cut block, yellow
Z = 4	0.33 × 0.32 × 0.21 mm
F(000) = 352

Data collection top

Bruker APEXII CCD diffractometer	1115 independent reflections
Radiation source: fine-focus sealed tube	883 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.028
Detector resolution: 8.3660 pixels mm^-1	θ_max = 27.1°, θ_min = 2.5°
phi and ω scans	h = −13→13
Absorption correction: multi-scan (SADABS; Bruker, 2014)	k = −8→8
T_min = 0.954, T_max = 1.000	l = −16→16
11353 measured reflections

Refinement top

Refinement on F²	2 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.040	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.116	w = 1/[σ²(F_o²) + (0.0555P)² + 0.1911P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max < 0.001
1115 reflections	Δρ_max = 0.25 e Å⁻³
80 parameters	Δρ_min = −0.19 e Å⁻³

Special details top

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

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
O1	0.39680 (11)	0.250000	0.32229 (9)	0.0446 (4)
N1	0.64524 (14)	0.250000	0.28016 (11)	0.0448 (4)
H1N	0.5657 (16)	0.250000	0.2566 (16)	0.054*
H2N	0.7141 (16)	0.250000	0.2431 (15)	0.054*
C1	0.55346 (14)	0.250000	0.45470 (11)	0.0281 (4)
C2	0.65892 (14)	0.250000	0.38534 (12)	0.0308 (4)
C7	0.42132 (14)	0.250000	0.41648 (12)	0.0314 (4)
C6	0.57905 (15)	0.250000	0.56227 (12)	0.0320 (4)
H6	0.510103	0.250000	0.607801	0.038*
C5	0.69982 (16)	0.250000	0.60405 (12)	0.0352 (4)
C8	0.31262 (15)	0.250000	0.49238 (13)	0.0374 (4)
H8A	0.326942	0.347668	0.544295	0.056*	0.5
H8B	0.306872	0.125247	0.525175	0.056*	0.5
H8C	0.234499	0.277084	0.456228	0.056*	0.5
C3	0.78212 (15)	0.250000	0.42849 (13)	0.0363 (4)
H3	0.851834	0.250000	0.383748	0.044*
C4	0.80412 (15)	0.250000	0.53421 (14)	0.0369 (4)
C10	0.7192 (2)	0.250000	0.72029 (14)	0.0511 (5)
H10A	0.743203	0.377630	0.742750	0.077*	0.5
H10B	0.785360	0.159710	0.738081	0.077*	0.5
H10C	0.641263	0.212661	0.754040	0.077*	0.5
C9	0.93866 (18)	0.250000	0.57495 (18)	0.0587 (6)
H9A	0.956895	0.373156	0.606419	0.088*	0.5
H9B	0.996882	0.227695	0.518555	0.088*	0.5
H9C	0.948051	0.149149	0.625851	0.088*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0299 (6)	0.0696 (9)	0.0342 (7)	0.000	−0.0056 (5)	0.000
N1	0.0298 (8)	0.0746 (11)	0.0300 (8)	0.000	0.0048 (6)	0.000
C1	0.0234 (7)	0.0315 (8)	0.0294 (8)	0.000	0.0014 (6)	0.000
C2	0.0273 (8)	0.0345 (8)	0.0307 (8)	0.000	0.0029 (6)	0.000
C7	0.0261 (8)	0.0331 (8)	0.0349 (8)	0.000	−0.0018 (6)	0.000
C6	0.0310 (8)	0.0350 (8)	0.0300 (8)	0.000	0.0024 (6)	0.000
C5	0.0368 (9)	0.0364 (9)	0.0323 (8)	0.000	−0.0066 (7)	0.000
C8	0.0252 (8)	0.0433 (10)	0.0437 (10)	0.000	0.0032 (7)	0.000
C3	0.0237 (8)	0.0439 (9)	0.0414 (9)	0.000	0.0041 (7)	0.000
C4	0.0267 (8)	0.0390 (9)	0.0449 (9)	0.000	−0.0064 (7)	0.000
C10	0.0549 (12)	0.0631 (12)	0.0355 (10)	0.000	−0.0120 (8)	0.000
C9	0.0315 (10)	0.0784 (15)	0.0661 (14)	0.000	−0.0156 (9)	0.000

Geometric parameters (Å, º) top

O1—C7	1.2377 (19)	C8—H8Bⁱ	0.960 (10)
N1—C2	1.360 (2)	C8—H8Cⁱ	0.960 (7)
N1—H1N	0.887 (15)	C3—C4	1.378 (2)
N1—H2N	0.864 (15)	C3—H3	0.9300
C1—C6	1.408 (2)	C4—C9	1.505 (2)
C1—C2	1.420 (2)	C10—H10A	0.9600
C1—C7	1.470 (2)	C10—H10B	0.9600
C2—C3	1.406 (2)	C10—H10C	0.9600
C7—C8	1.500 (2)	C10—H10Aⁱ	0.960 (8)
C6—C5	1.375 (2)	C10—H10Bⁱ	0.960 (17)
C6—H6	0.9300	C10—H10Cⁱ	0.960 (9)
C5—C4	1.415 (2)	C9—H9A	0.9600
C5—C10	1.508 (2)	C9—H9B	0.9600
C8—H8A	0.9600	C9—H9C	0.9600
C8—H8B	0.9600	C9—H9Aⁱ	0.960 (19)
C8—H8C	0.9600	C9—H9Bⁱ	0.960 (10)
C8—H8Aⁱ	0.960 (17)	C9—H9Cⁱ	0.96 (3)

C2—N1—H1N	116.0 (14)	C5—C4—C9	120.25 (17)
C2—N1—H2N	117.4 (14)	C5—C10—H10A	109.5
H1N—N1—H2N	127 (2)	C5—C10—H10B	109.5
C6—C1—C2	117.90 (13)	H10A—C10—H10B	109.5
C6—C1—C7	120.50 (13)	C5—C10—H10C	109.5
C2—C1—C7	121.59 (14)	H10A—C10—H10C	109.5
N1—C2—C3	119.30 (14)	H10B—C10—H10C	109.5
N1—C2—C1	122.82 (14)	C5—C10—H10Aⁱ	109.47 (16)
C3—C2—C1	117.88 (14)	H10A—C10—H10Aⁱ	132.9
O1—C7—C1	121.51 (14)	H10B—C10—H10Aⁱ	31.1
O1—C7—C8	118.58 (14)	H10C—C10—H10Aⁱ	80.9
C1—C7—C8	119.91 (14)	C5—C10—H10Bⁱ	109.5 (4)
C5—C6—C1	123.96 (14)	H10A—C10—H10Bⁱ	31.1
C5—C6—H6	118.0	H10B—C10—H10Bⁱ	80.9
C1—C6—H6	118.0	H10C—C10—H10Bⁱ	132.9
C6—C5—C4	117.63 (15)	H10Aⁱ—C10—H10Bⁱ	109.5
C6—C5—C10	120.72 (15)	C5—C10—H10Cⁱ	109.5 (2)
C4—C5—C10	121.65 (15)	H10A—C10—H10Cⁱ	80.9
C7—C8—H8A	109.5	H10B—C10—H10Cⁱ	132.9
C7—C8—H8B	109.5	H10C—C10—H10Cⁱ	31.1
H8A—C8—H8B	109.5	H10Aⁱ—C10—H10Cⁱ	109.5
C7—C8—H8C	109.5	H10Bⁱ—C10—H10Cⁱ	109.5
H8A—C8—H8C	109.5	C4—C9—H9A	109.5
H8B—C8—H8C	109.5	C4—C9—H9B	109.5
C7—C8—H8Aⁱ	109.5 (4)	H9A—C9—H9B	109.5
H8A—C8—H8Aⁱ	89.1	C4—C9—H9C	109.5
H8B—C8—H8Aⁱ	22.4	H9A—C9—H9C	109.5
H8C—C8—H8Aⁱ	127.3	H9B—C9—H9C	109.5
C7—C8—H8Bⁱ	109.5 (2)	C4—C9—H9Aⁱ	109.5 (4)
H8A—C8—H8Bⁱ	22.4	H9A—C9—H9Aⁱ	124.4
H8B—C8—H8Bⁱ	127.3	H9B—C9—H9Aⁱ	92.9
H8C—C8—H8Bⁱ	89.1	H9C—C9—H9Aⁱ	18.4
H8Aⁱ—C8—H8Bⁱ	109.5	C4—C9—H9Bⁱ	109.5 (2)
C7—C8—H8Cⁱ	109.47 (17)	H9A—C9—H9Bⁱ	92.9
H8A—C8—H8Cⁱ	127.3	H9B—C9—H9Bⁱ	18.4
H8B—C8—H8Cⁱ	89.1	H9C—C9—H9Bⁱ	124.4
H8C—C8—H8Cⁱ	22.4	H9Aⁱ—C9—H9Bⁱ	109.5
H8Aⁱ—C8—H8Cⁱ	109.5	C4—C9—H9Cⁱ	109.5 (6)
H8Bⁱ—C8—H8Cⁱ	109.5	H9A—C9—H9Cⁱ	18.4
C4—C3—C2	122.87 (14)	H9B—C9—H9Cⁱ	124.4
C4—C3—H3	118.6	H9C—C9—H9Cⁱ	92.9
C2—C3—H3	118.6	H9Aⁱ—C9—H9Cⁱ	109.5
C3—C4—C5	119.75 (14)	H9Bⁱ—C9—H9Cⁱ	109.5
C3—C4—C9	120.00 (16)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1	0.89 (2)	1.96 (2)	2.6603 (19)	135 (2)
N1—H2N···O1ⁱⁱ	0.86 (2)	2.09 (2)	2.9478 (18)	170 (2)

Symmetry code: (ii) x+1/2, y, −z+1/2.

Acknowledgements

We thank the Missouri State University Provost Incentive Fund that funded the purchase of the X-ray diffractometer.

References

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