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Acta Cryst. (2008). E64, o1084    [ doi:10.1107/S1600536808014177 ]

Ethyl 5-acetyl-2-amino-4-methylthiophene-3-carboxylate

M. Akkurt, S. Ö. Yildirim, A. M. Asiri and V. McKee

Abstract top

In the title compound, C10H13NO3S, prepared in a one-pot reaction, the molecular conformation is stabilized by an intramolecular N-H...O hydrogen bond. The packing is consolidated by further N-H...O links. The H atoms of two of the methyl groups are disordered over two sets of sites with equal occupancies.

Comment top

2-Aminothiophene derivatives are important intermediates in the synthesis of a variety of agrochemicals, dyes and pharmacologically active compounds (Sabnis et al., 1999). The most convergent and well established classical approach for the preparation of 2-aminothiophenes is Gewald's method (Gewald et al., 1966), which involves the multicomponent condensation of a ketone with an activated nitrile and elemental sulfur in the presence of diethylamine as a catalyst.

As a part of an ongoing investigation into the development of anil derivatives, we here report the structure of the title compound, (I).

All bond lengths and angles in (I) (Fig. 1) are within their normal ranges (Akkurt et al., 2008; Allen et al., 1987). The thiophene ring is almost planar, with a maximum deviation of -0.009 (1) Å for C6. The structure is stabilized by weak intra molecular C—H···O and N—H···O, and intermolecular N—H···O hydrogen bonding interactions (Table 1 and Fig. 2).

Related literature top

For related literature, see: Gewald et al. (1966); Sabnis et al. (1999); Akkurt et al. (2008); Allen et al. (1987).

Experimental top

A mixture of ethyl cyanoacetate (11.3 g, 0.10 mol) and acetyl acetone (10.22 g, 0.10 mol) in absolute ethanol (20 ml) was added to a solution of elemental sulfur (3.2 g, 0.10 mol) and diethylamine (5 ml) in 50 ml absolute ethanol at room temperature. The reaction mixture was refluxed for 3 h and then cooled. The precipitated product was filtered, washed with ethanol, dried and recrystallized from ethanol as orange blocks of (I) [yield: 52%, m.p. 435-437 K]. IR (cm-1) 3408, 3294 (NH), 1666 (CO), 1605, 1586,1253. 1H-NMR (CDCl3): 1.38 (t, 3H, CH3CH2O),2.43 (s, 3H, COCH3), 2.7 (s, 3H, CH3), 4.32 (q, 2H, OCH2),6.67 (broad s, 2H, NH2).

Refinement top

All the H atoms were positioned geometrically (C—H = 0.96 - 0.97 Å and N—H = 0.86 Å) and refined as riding with Uiso = 1.2Ueq(carrier) (1.5Ueq for methyl C). The methyl H atoms attached to C1 and C5 were refined as disordered over two sets of sites.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: APEX2 (Bruker, 2005); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. View of the molecular structure of (I) with displacement ellipsoids for non-H atoms drawn at the 50% probability level. The hydrogen bond is shown as a dashed line.
[Figure 2] Fig. 2. View of the packing and hydrogen bonding in (I).
Ethyl 5-acetyl-2-amino-4-methylthiophene-3-carboxylate top
Crystal data top
C10H13NO3SF(000) = 480
Mr = 227.28Dx = 1.423 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4913 reflections
a = 7.5397 (3) Åθ = 2.5–31.1°
b = 8.4514 (3) ŵ = 0.29 mm−1
c = 16.7058 (6) ÅT = 150 K
β = 94.465 (1)°Block, orange
V = 1061.28 (7) Å30.29 × 0.26 × 0.10 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer		3400 independent reflections
Radiation source: sealed tube2944 reflections with I > 2σ(I)
graphiteRint = 0.025
φ and ω scansθmax = 31.8°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		h = −11→10
Tmin = 0.920, Tmax = 0.971k = −12→12
12338 measured reflectionsl = −23→24
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.111H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.06P)2 + 0.3751P]
where P = (Fo2 + 2Fc2)/3
3400 reflections(Δ/σ)max = 0.001
136 parametersΔρmax = 0.44 e Å−3
0 restraintsΔρmin = −0.34 e Å−3
Crystal data top
C10H13NO3SV = 1061.28 (7) Å3
Mr = 227.28Z = 4
Monoclinic, P21/nMo Kα radiation
a = 7.5397 (3) ŵ = 0.29 mm−1
b = 8.4514 (3) ÅT = 150 K
c = 16.7058 (6) Å0.29 × 0.26 × 0.10 mm
β = 94.465 (1)°
Data collection top
Bruker APEXII CCD
diffractometer		3400 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		2944 reflections with I > 2σ(I)
Tmin = 0.920, Tmax = 0.971Rint = 0.025
12338 measured reflectionsθmax = 31.8°
Refinement top
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.111Δρmax = 0.44 e Å−3
S = 1.05Δρmin = −0.34 e Å−3
3400 reflectionsAbsolute structure: ?
136 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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
xyzUiso*/UeqOcc. (<1)
S10.74240 (4)0.44716 (4)0.82882 (2)0.0234 (1)
O10.58575 (14)0.74136 (13)0.79734 (6)0.0324 (3)
O20.94110 (15)0.13922 (12)1.03979 (6)0.0315 (3)
O30.83808 (13)0.32842 (11)1.11776 (5)0.0251 (3)
N10.88307 (16)0.17090 (13)0.87660 (6)0.0263 (3)
C10.5682 (2)0.86338 (17)0.92406 (8)0.0307 (4)
C20.61541 (17)0.72854 (15)0.87090 (7)0.0240 (3)
C30.69568 (16)0.58332 (15)0.90307 (7)0.0210 (3)
C40.74019 (15)0.52653 (14)0.97964 (7)0.0191 (3)
C50.71928 (18)0.61996 (15)1.05495 (7)0.0249 (3)
C60.81050 (15)0.36847 (14)0.97838 (7)0.0194 (3)
C70.82188 (16)0.31123 (14)0.89967 (7)0.0208 (3)
C80.87045 (16)0.26784 (14)1.04635 (7)0.0207 (3)
C90.90152 (19)0.23865 (16)1.18821 (7)0.0272 (3)
C100.8610 (2)0.33700 (19)1.25956 (8)0.0325 (4)
HN1A0.921900.102900.912000.0320*
H1A0.517300.948000.891600.0460*0.500
H1B0.673600.900400.954300.0460*0.500
H1C0.483700.827800.960200.0460*0.500
H1D0.599100.836100.979200.0460*0.500
H1E0.442800.883800.916400.0460*0.500
H1F0.632600.956300.910500.0460*0.500
HN1B0.883500.148900.826400.0320*
H5A0.758000.557101.100900.0370*0.500
H5B0.596500.648001.057700.0370*0.500
H5C0.789900.714401.054300.0370*0.500
H5D0.671600.722501.041000.0370*0.500
H5E0.833200.631701.084300.0370*0.500
H5F0.639700.565301.087600.0370*0.500
H9A1.028500.219901.188300.0330*
H9B0.841200.137401.189200.0330*
H10A0.900500.282201.308000.0490*
H10B0.735100.354901.258500.0490*
H10C0.921500.436701.257700.0490*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0306 (2)0.0254 (2)0.0142 (1)−0.0032 (1)0.0017 (1)−0.0009 (1)
O10.0409 (6)0.0366 (5)0.0198 (4)0.0027 (4)0.0031 (4)0.0076 (4)
O20.0468 (6)0.0238 (4)0.0241 (5)0.0083 (4)0.0037 (4)−0.0003 (3)
O30.0348 (5)0.0258 (4)0.0147 (4)0.0055 (4)0.0015 (3)0.0012 (3)
N10.0373 (6)0.0222 (5)0.0197 (5)−0.0009 (4)0.0038 (4)−0.0052 (4)
C10.0386 (7)0.0263 (6)0.0271 (6)0.0064 (5)0.0016 (5)0.0038 (5)
C20.0248 (5)0.0262 (6)0.0212 (5)−0.0031 (4)0.0027 (4)0.0040 (4)
C30.0245 (5)0.0224 (5)0.0163 (5)−0.0032 (4)0.0023 (4)−0.0006 (4)
C40.0200 (5)0.0211 (5)0.0164 (5)−0.0030 (4)0.0022 (4)−0.0010 (4)
C50.0327 (6)0.0246 (6)0.0174 (5)0.0024 (5)0.0017 (4)−0.0026 (4)
C60.0216 (5)0.0206 (5)0.0161 (5)−0.0026 (4)0.0018 (4)−0.0013 (4)
C70.0228 (5)0.0217 (5)0.0180 (5)−0.0045 (4)0.0024 (4)−0.0017 (4)
C80.0234 (5)0.0215 (5)0.0173 (5)−0.0025 (4)0.0019 (4)−0.0008 (4)
C90.0360 (7)0.0270 (6)0.0185 (5)0.0027 (5)0.0010 (5)0.0057 (4)
C100.0407 (7)0.0392 (7)0.0179 (5)0.0024 (6)0.0044 (5)0.0023 (5)
Geometric parameters (Å, °) top
S1—C31.7479 (13)C1—H1A0.9600
S1—C71.7232 (12)C1—H1B0.9600
O1—C21.2366 (15)C1—H1C0.9600
O2—C81.2192 (16)C1—H1D0.9600
O3—C81.3380 (15)C1—H1E0.9600
O3—C91.4498 (15)C1—H1F0.9600
N1—C71.3400 (16)C5—H5A0.9600
N1—HN1A0.8600C5—H5B0.9600
N1—HN1B0.8600C5—H5C0.9600
C1—C21.5044 (19)C5—H5D0.9600
C2—C31.4529 (18)C5—H5E0.9600
C3—C41.3829 (17)C5—H5F0.9600
C4—C61.4379 (17)C9—H9A0.9700
C4—C51.5040 (17)C9—H9B0.9700
C6—C71.4100 (17)C10—H10A0.9600
C6—C81.4619 (17)C10—H10B0.9600
C9—C101.5039 (19)C10—H10C0.9600
C3—S1—C791.72 (6)H1C—C1—H1D56.00
C8—O3—C9116.87 (10)H1C—C1—H1E56.00
HN1A—N1—HN1B120.00H1C—C1—H1F141.00
C7—N1—HN1A120.00H1D—C1—H1E110.00
C7—N1—HN1B120.00H1D—C1—H1F109.00
O1—C2—C1119.18 (12)H1E—C1—H1F109.00
O1—C2—C3118.66 (11)C4—C5—H5A109.00
C1—C2—C3122.17 (11)C4—C5—H5B110.00
S1—C3—C2113.26 (9)C4—C5—H5C109.00
C2—C3—C4134.38 (11)C4—C5—H5D109.00
S1—C3—C4112.34 (9)C4—C5—H5E109.00
C5—C4—C6124.25 (10)C4—C5—H5F109.00
C3—C4—C6111.84 (10)H5A—C5—H5B109.00
C3—C4—C5123.91 (11)H5A—C5—H5C110.00
C4—C6—C7112.44 (10)H5A—C5—H5D141.00
C4—C6—C8128.40 (11)H5A—C5—H5E56.00
C7—C6—C8119.16 (10)H5A—C5—H5F56.00
N1—C7—C6128.26 (11)H5B—C5—H5C109.00
S1—C7—N1120.11 (9)H5B—C5—H5D56.00
S1—C7—C6111.64 (9)H5B—C5—H5E141.00
O2—C8—O3122.18 (11)H5B—C5—H5F56.00
O2—C8—C6124.04 (11)H5C—C5—H5D56.00
O3—C8—C6113.77 (10)H5C—C5—H5E56.00
O3—C9—C10106.24 (11)H5C—C5—H5F141.00
C2—C1—H1A109.00H5D—C5—H5E109.00
C2—C1—H1B109.00H5D—C5—H5F109.00
C2—C1—H1C109.00H5E—C5—H5F109.00
C2—C1—H1D109.00O3—C9—H9A110.00
C2—C1—H1E109.00O3—C9—H9B110.00
C2—C1—H1F109.00C10—C9—H9A111.00
H1A—C1—H1B109.00C10—C9—H9B110.00
H1A—C1—H1C109.00H9A—C9—H9B109.00
H1A—C1—H1D141.00C9—C10—H10A109.00
H1A—C1—H1E56.00C9—C10—H10B110.00
H1A—C1—H1F56.00C9—C10—H10C109.00
H1B—C1—H1C110.00H10A—C10—H10B109.00
H1B—C1—H1D56.00H10A—C10—H10C110.00
H1B—C1—H1E141.00H10B—C10—H10C109.00
H1B—C1—H1F56.00
C7—S1—C3—C2−178.44 (10)C2—C3—C4—C6177.16 (13)
C7—S1—C3—C40.21 (10)C3—C4—C6—C71.69 (15)
C3—S1—C7—N1−179.68 (11)C3—C4—C6—C8−179.30 (12)
C3—S1—C7—C60.76 (10)C5—C4—C6—C7−177.67 (11)
C9—O3—C8—O23.93 (18)C5—C4—C6—C81.35 (19)
C9—O3—C8—C6−177.14 (10)C4—C6—C7—S1−1.52 (13)
C8—O3—C9—C10175.85 (11)C4—C6—C7—N1178.96 (12)
O1—C2—C3—S11.18 (16)C8—C6—C7—S1179.36 (9)
O1—C2—C3—C4−177.07 (13)C8—C6—C7—N1−0.2 (2)
C1—C2—C3—S1−178.56 (10)C4—C6—C8—O2−174.17 (12)
C1—C2—C3—C43.2 (2)C4—C6—C8—O36.93 (18)
S1—C3—C4—C5178.25 (10)C7—C6—C8—O24.79 (19)
S1—C3—C4—C6−1.10 (13)C7—C6—C8—O3−174.12 (11)
C2—C3—C4—C5−3.5 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—HN1A···O20.862.152.7404 (14)125
N1—HN1A···O2i0.862.403.2077 (15)156
N1—HN1B···O1ii0.862.242.9933 (14)147
C5—H5A···O30.962.042.7978 (16)135
Symmetry codes: (i) −x+2, −y, −z+2; (ii) −x+3/2, y−1/2, −z+3/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—HN1A···O20.862.152.7404 (14)125
N1—HN1A···O2i0.862.403.2077 (15)156
N1—HN1B···O1ii0.862.242.9933 (14)147
C5—H5A···O30.962.042.7978 (16)135
Symmetry codes: (i) −x+2, −y, −z+2; (ii) −x+3/2, y−1/2, −z+3/2.
references
References top

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Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.

Gewald, K., Schinke, E. & Bottcher, H. (1966). Chem. Ber. 99, 94–100.

Sabnis, R. W., Rangnekar, D. W. & Sonawane, N. D. (1999). J. Heterocycl. Chem. 36, 333–345.

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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.