Ethyl 2-acetyl­amino-4,5,6,7-tetra­hydro-1-benzothio­phene-3-carboxyl­ate

Harrison, W.T.A.; Yathirajan, H.S.; Ashalatha, B.V.; Vijaya Raj, K.K.; Narayana, B.

doi:10.1107/S1600536806030133

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 62| Part 9| September 2006| Pages o3732-o3734

https://doi.org/10.1107/S1600536806030133

Ethyl 2-acetylamino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate

William T. A. Harrison,^a ^* H. S. Yathirajan,^b B. V. Ashalatha,^c K. K. Vijaya Raj ^c and B. Narayana ^c

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, ^bDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India, and ^cDepartment of Chemistry, Mangalore University, Mangalagangotri 574 199, India
^*Correspondence e-mail: w.harrison@abdn.ac.uk

(Received 6 July 2006; accepted 1 August 2006; online 9 August 2006)

The geometrical parameters for the title compound, C₁₃H₁₇NO₃S, are normal. The planar molecular conformation is reinforced by an intramolecular N—H⋯O interaction.

Comment

Thiophene derivatives are known to exhibit an array of biological effects, including analgesic and anti-inflammatory activities (Ramanathan & Namboothiri, 1978 ; Cannito et al., 1990 ). As part of our own research in this area, the structure of the title compound, (I) (Fig. 1), is presented.

The geometric parameters for (I) are normal. The five-membered C1/C2/C6/C7/S1 ring is almost planar (r.m.s. deviation from the mean plane = 0.013 Å). The C1–C6 ring is in a half-chair conformation (Table 1), with atoms C1, C2, C5 and C6 almost co-planar (r.m.s. deviation = 0.003 Å) and atoms C3 and C4 displaced from this plane by −0.480 (3) and 0.277 (3) Å, respectively. An intramolecular N—H⋯O bond (Table 2) helps to establish the molecular conformation. Overall, the molecule of (I) is approximately planar.

The molecular packing for (I) comprises undulating sheets lying parallel to the (10 $[\overline{1}]$ ) plane (Fig. 2). Within these sheets, the shortest intermolecular contacts are C—H⋯O interactions (Table 2).

Figure 1
The molecular structure of (I)

, showing 50% probability displacement ellipsoids and arbitrary spheres for the H atoms. The intramolecular hydrogen bond is indicated by a dashed line.

Figure 2
A view of the unit-cell contents of (I)

, with H atoms (except H1) omitted for clarity.

Experimental

Ethyl-2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate, (II), was prepared from cyclohexanone, sulfur and ethyl cyanoacetate by a one-pot thiolation-heterocyclization reaction (Gewald et al., 1966 ). A mixture of (II) (3.5 g, 0.015 mol), acetic anhydride (14 ml) and zinc dust (0.883 g, 0.015 mol) was refluxed for 2 h. The reaction mixture was cooled to room temperature and the solid product was recovered. The crude product was dissolved in warm (318 K) methanol (35 ml) and filtered. The product was recrystallized from acetone to yield colourless crystals of (I) (yield 84.3%; m.p. 388 K). IR (KBr, cm⁻¹): 3436 and 3244 (—NH—), 2931 and 2873 (—CH—), 1666 and 1546 (C=O) and 1250 (C—O). Elemental analysis, found: C 58.18, H 6.32, N 5.16%; calculated: C58.40, H 6.41, N 5.24%.

Crystal data

C₁₃H₁₇NO₃S
M_r = 267.34
Monoclinic, P 2₁ /c
a = 10.2987 (4) Å
b = 16.6174 (5) Å
c = 7.8510 (3) Å
β = 108.4381 (18)°
V = 1274.63 (8) Å³
Z = 4
D_x = 1.393 Mg m⁻³
Mo Kα radiation
μ = 0.25 mm⁻¹
T = 120 (2) K
Cut block, colourless
0.44 × 0.30 × 0.18 mm

Data collection

Nonius KappaCCD diffractometer
ω and φ scans
Absorption correction: multi-scan (SADABS; Bruker, 2003 ) T_min = 0.897, T_max = 0.958
16538 measured reflections
2917 independent reflections
2338 reflections with I > 2σ(I)
R_int = 0.039
θ_max = 27.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.091
S = 1.05
2917 reflections
168 parameters
H atoms treated by a mixture of independent and constrained refinement
w = 1/[σ²(F_o²) + (0.0407P)² + 0.574P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Table 1
Selected torsion angles (°)

C1—C2—C3—C4	48.83 (16)
C2—C3—C4—C5	−63.48 (17)
C3—C4—C5—C6	42.28 (18)
C4—C5—C6—C1	−10.54 (19)
C5—C6—C1—C2	−0.9 (2)
C6—C1—C2—C3	−18.7 (2)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2	0.858 (18)	1.979 (18)	2.6798 (17)	138.1 (16)
C2—H2A⋯O2ⁱ	0.99	2.44	3.370 (2)	157
Symmetry code: (i) $[-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

The N-bound H atom was located in a difference map and its position was refined freely, with U_iso(H) = 1.2U_eq(N). The C-bound H atoms were placed in idealised locations (C—H = 0.98–0.99 Å) and refined as riding, with U_iso(H) = 1.2U_eq(C) or 1.5U_eq(methyl C). The methyl groups were allowed to rotate about their local threefold axes to fit the electron density.

Data collection: COLLECT (Nonius, 1998 ); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997) and SORTAV (Blessing, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536806030133/bi2039sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536806030133/bi2039Isup2.hkl

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997) and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Ethyl 2-(acetylamino)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate top

Crystal data top

C₁₃H₁₇NO₃S	F(000) = 568
M_r = 267.34	D_x = 1.393 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3015 reflections
a = 10.2987 (4) Å	θ = 1.0–27.5°
b = 16.6174 (5) Å	µ = 0.25 mm⁻¹
c = 7.8510 (3) Å	T = 120 K
β = 108.4381 (18)°	Cut block, colourless
V = 1274.63 (8) Å³	0.44 × 0.30 × 0.18 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	2917 independent reflections
Radiation source: fine-focus sealed tube	2338 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
ω and φ scans	θ_max = 27.5°, θ_min = 3.2°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −13→13
T_min = 0.897, T_max = 0.958	k = −21→20
16538 measured reflections	l = −10→10

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.091	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0407P)² + 0.574P] where P = (F_o² + 2F_c²)/3
2917 reflections	(Δ/σ)_max = 0.001
168 parameters	Δρ_max = 0.28 e Å⁻³
0 restraints	Δρ_min = −0.28 e Å⁻³

Special details top

Experimental. IR (KBr, cm^-1): 3436 and 3244 (—NH—), 2931 and 2873 (—CH—), 1666 and 1546 (C═O) and 1250 (C—O). Elemental analysis, found: C 58.18, H 6.32, N 5.16%; calculated: C58.40, H 6.41, N 5.24%.

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	0.42025 (15)	0.34938 (9)	0.5719 (2)	0.0190 (3)
C2	0.36910 (16)	0.27403 (9)	0.4663 (2)	0.0232 (3)
H2A	0.3934	0.2266	0.5464	0.028*
H2B	0.4126	0.2679	0.3712	0.028*
C3	0.21396 (16)	0.27903 (9)	0.3819 (2)	0.0232 (3)
H3A	0.1817	0.2347	0.2944	0.028*
H3B	0.1696	0.2731	0.4762	0.028*
C4	0.17450 (16)	0.35977 (9)	0.2872 (2)	0.0229 (3)
H4A	0.0746	0.3605	0.2246	0.028*
H4B	0.2214	0.3658	0.1956	0.028*
C5	0.21240 (15)	0.43102 (9)	0.41786 (19)	0.0194 (3)
H5A	0.2108	0.4812	0.3493	0.023*
H5B	0.1433	0.4362	0.4808	0.023*
C6	0.35228 (15)	0.42071 (9)	0.55453 (19)	0.0178 (3)
C7	0.43107 (14)	0.48049 (9)	0.67846 (19)	0.0175 (3)
C8	0.55668 (15)	0.45085 (9)	0.78253 (19)	0.0189 (3)
C9	0.78203 (16)	0.46767 (10)	1.0084 (2)	0.0232 (3)
C10	0.86975 (16)	0.52769 (10)	1.1382 (2)	0.0276 (4)
H10A	0.8119	0.5710	1.1592	0.041*
H10B	0.9375	0.5504	1.0878	0.041*
H10C	0.9169	0.5008	1.2521	0.041*
C11	0.39415 (15)	0.56423 (9)	0.6996 (2)	0.0191 (3)
C12	0.23372 (17)	0.66948 (9)	0.5971 (2)	0.0261 (4)
H12A	0.3078	0.7041	0.5829	0.031*
H12B	0.2198	0.6825	0.7131	0.031*
C13	0.10391 (17)	0.68309 (10)	0.4450 (3)	0.0323 (4)
H13A	0.0775	0.7398	0.4423	0.048*
H13B	0.0309	0.6494	0.4621	0.048*
H13C	0.1186	0.6689	0.3313	0.048*
N1	0.65371 (13)	0.49412 (8)	0.91396 (17)	0.0208 (3)
H1	0.6261 (17)	0.5419 (11)	0.925 (2)	0.025*
O1	0.82149 (11)	0.40043 (7)	0.98601 (16)	0.0315 (3)
O2	0.46870 (11)	0.61218 (6)	0.80471 (15)	0.0253 (3)
O3	0.26963 (11)	0.58460 (6)	0.59197 (14)	0.0220 (2)
S1	0.58051 (4)	0.35234 (2)	0.73354 (5)	0.02108 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0201 (7)	0.0197 (7)	0.0179 (7)	0.0006 (6)	0.0067 (6)	0.0014 (6)
C2	0.0301 (8)	0.0172 (8)	0.0221 (8)	0.0028 (6)	0.0077 (6)	−0.0015 (6)
C3	0.0293 (8)	0.0183 (8)	0.0211 (7)	−0.0028 (6)	0.0068 (6)	−0.0020 (6)
C4	0.0257 (8)	0.0202 (8)	0.0205 (8)	−0.0008 (6)	0.0038 (6)	−0.0008 (6)
C5	0.0199 (7)	0.0177 (7)	0.0195 (7)	0.0006 (6)	0.0048 (6)	0.0009 (6)
C6	0.0213 (7)	0.0178 (7)	0.0161 (7)	−0.0009 (6)	0.0087 (6)	0.0012 (6)
C7	0.0187 (7)	0.0185 (7)	0.0170 (7)	−0.0008 (6)	0.0082 (6)	0.0010 (6)
C8	0.0214 (7)	0.0193 (7)	0.0180 (7)	−0.0010 (6)	0.0092 (6)	0.0016 (6)
C9	0.0212 (8)	0.0291 (9)	0.0199 (7)	−0.0011 (6)	0.0072 (6)	0.0039 (7)
C10	0.0228 (8)	0.0335 (9)	0.0232 (8)	−0.0022 (7)	0.0025 (6)	0.0028 (7)
C11	0.0200 (7)	0.0196 (7)	0.0194 (7)	−0.0020 (6)	0.0088 (6)	0.0003 (6)
C12	0.0299 (9)	0.0138 (7)	0.0353 (9)	0.0028 (6)	0.0114 (7)	−0.0025 (7)
C13	0.0251 (9)	0.0219 (8)	0.0483 (11)	0.0033 (7)	0.0094 (8)	0.0038 (8)
N1	0.0194 (6)	0.0211 (7)	0.0213 (6)	−0.0016 (5)	0.0056 (5)	−0.0002 (5)
O1	0.0251 (6)	0.0326 (7)	0.0322 (7)	0.0046 (5)	0.0024 (5)	−0.0019 (5)
O2	0.0264 (6)	0.0203 (6)	0.0274 (6)	−0.0029 (5)	0.0057 (5)	−0.0048 (5)
O3	0.0213 (5)	0.0155 (5)	0.0279 (6)	0.0020 (4)	0.0061 (4)	−0.0008 (4)
S1	0.0205 (2)	0.0197 (2)	0.0226 (2)	0.00291 (15)	0.00611 (14)	0.00109 (15)

Geometric parameters (Å, º) top

C1—C6	1.361 (2)	C8—N1	1.3884 (19)
C1—C2	1.502 (2)	C8—S1	1.7170 (15)
C1—S1	1.7356 (15)	C9—O1	1.221 (2)
C2—C3	1.526 (2)	C9—N1	1.3674 (19)
C2—H2A	0.990	C9—C10	1.505 (2)
C2—H2B	0.990	C10—H10A	0.980
C3—C4	1.525 (2)	C10—H10B	0.980
C3—H3A	0.990	C10—H10C	0.980
C3—H3B	0.990	C11—O2	1.2266 (18)
C4—C5	1.534 (2)	C11—O3	1.3370 (18)
C4—H4A	0.990	C12—O3	1.4619 (17)
C4—H4B	0.990	C12—C13	1.502 (2)
C5—C6	1.509 (2)	C12—H12A	0.990
C5—H5A	0.990	C12—H12B	0.990
C5—H5B	0.990	C13—H13A	0.980
C6—C7	1.446 (2)	C13—H13B	0.980
C7—C8	1.384 (2)	C13—H13C	0.980
C7—C11	1.466 (2)	N1—H1	0.858 (18)

C6—C1—C2	126.24 (14)	C7—C8—N1	124.98 (14)
C6—C1—S1	112.86 (11)	C7—C8—S1	112.34 (11)
C2—C1—S1	120.90 (11)	N1—C8—S1	122.68 (11)
C1—C2—C3	109.31 (12)	O1—C9—N1	121.65 (15)
C1—C2—H2A	109.8	O1—C9—C10	123.24 (14)
C3—C2—H2A	109.8	N1—C9—C10	115.11 (14)
C1—C2—H2B	109.8	C9—C10—H10A	109.5
C3—C2—H2B	109.8	C9—C10—H10B	109.5
H2A—C2—H2B	108.3	H10A—C10—H10B	109.5
C4—C3—C2	109.91 (13)	C9—C10—H10C	109.5
C4—C3—H3A	109.7	H10A—C10—H10C	109.5
C2—C3—H3A	109.7	H10B—C10—H10C	109.5
C4—C3—H3B	109.7	O2—C11—O3	122.13 (14)
C2—C3—H3B	109.7	O2—C11—C7	124.28 (14)
H3A—C3—H3B	108.2	O3—C11—C7	113.59 (12)
C3—C4—C5	112.40 (12)	O3—C12—C13	107.03 (13)
C3—C4—H4A	109.1	O3—C12—H12A	110.3
C5—C4—H4A	109.1	C13—C12—H12A	110.3
C3—C4—H4B	109.1	O3—C12—H12B	110.3
C5—C4—H4B	109.1	C13—C12—H12B	110.3
H4A—C4—H4B	107.9	H12A—C12—H12B	108.6
C6—C5—C4	111.81 (12)	C12—C13—H13A	109.5
C6—C5—H5A	109.3	C12—C13—H13B	109.5
C4—C5—H5A	109.3	H13A—C13—H13B	109.5
C6—C5—H5B	109.3	C12—C13—H13C	109.5
C4—C5—H5B	109.3	H13A—C13—H13C	109.5
H5A—C5—H5B	107.9	H13B—C13—H13C	109.5
C1—C6—C7	111.67 (13)	C9—N1—C8	125.56 (14)
C1—C6—C5	120.99 (13)	C9—N1—H1	122.4 (12)
C7—C6—C5	127.33 (13)	C8—N1—H1	111.9 (12)
C8—C7—C6	111.94 (13)	C11—O3—C12	115.31 (12)
C8—C7—C11	119.90 (13)	C8—S1—C1	91.18 (7)
C6—C7—C11	128.15 (13)

C1—C2—C3—C4	48.83 (16)	C6—C7—C8—S1	−0.19 (16)
C2—C3—C4—C5	−63.48 (17)	C11—C7—C8—S1	−178.84 (11)
C3—C4—C5—C6	42.28 (18)	C8—C7—C11—O2	0.7 (2)
C4—C5—C6—C1	−10.54 (19)	C6—C7—C11—O2	−177.70 (14)
C5—C6—C1—C2	−0.9 (2)	C8—C7—C11—O3	−179.44 (12)
C6—C1—C2—C3	−18.7 (2)	C6—C7—C11—O3	2.1 (2)
S1—C1—C2—C3	161.76 (11)	O1—C9—N1—C8	−1.7 (2)
C2—C1—C6—C7	179.52 (14)	C10—C9—N1—C8	177.50 (13)
S1—C1—C6—C7	−0.95 (16)	C7—C8—N1—C9	−174.86 (14)
S1—C1—C6—C5	178.59 (11)	S1—C8—N1—C9	5.9 (2)
C4—C5—C6—C7	168.93 (14)	O2—C11—O3—C12	5.2 (2)
C1—C6—C7—C8	0.73 (18)	C7—C11—O3—C12	−174.69 (12)
C5—C6—C7—C8	−178.78 (13)	C13—C12—O3—C11	169.63 (13)
C1—C6—C7—C11	179.25 (14)	C7—C8—S1—C1	−0.29 (12)
C5—C6—C7—C11	−0.3 (2)	N1—C8—S1—C1	179.02 (13)
C6—C7—C8—N1	−179.48 (13)	C6—C1—S1—C8	0.73 (12)
C11—C7—C8—N1	1.9 (2)	C2—C1—S1—C8	−179.71 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2	0.858 (18)	1.979 (18)	2.6798 (17)	138.1 (16)
C2—H2A···O2ⁱ	0.99	2.44	3.370 (2)	157

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

Acknowledgements

The authors thank the EPSRC National Crystallography Service, University of Southampton, for data collection. ABV thanks Mangalore University for the provision of research facilities.

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