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Acta Crystallogr Sect E Struct Rep Online. 2008 May 1; 64(Pt 5): o869.
Published online 2008 April 18. doi:  10.1107/S1600536808010489
PMCID: PMC2961328

Methyl 2-(2-hydroxy­benzyl­ideneamino)-4,5,6,7-tetra­hydro-1-benzothio­phene-3-carboxyl­ate

Abstract

In the title compound, C17H17NO3S, the cyclohexene ring is essentially planar, with a maximum deviation of 0.006 (1) Å. The cyclo­hexene ring adopts a half-chair conformation. The dihedral angle between the thio­phene and benzene rings is 29.7 (1)°. The mol­ecular structure exhibits intra­molecular O—H(...)O, O—H(...)N and C—H(...)S hydrogen bonds, which generate one S(5) and two S(6) motifs. There is also a C—H(...)π inter­action between the cyclo­hexene ring system and the π-system of the benzene ring.

Related literature

For related literature, see: Akkurt et al. (2008 [triangle]); Allen et al. (1987 [triangle]); Asiri & Badahdah (2007 [triangle]); Bernstein et al. (1995 [triangle]); Cremer & Pople (1975 [triangle]); Etter (1990 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-0o869-scheme1.jpg

Experimental

Crystal data

  • C17H17NO3S
  • M r = 315.39
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0o869-efi1.jpg
  • a = 7.6107 (4) Å
  • b = 21.2154 (9) Å
  • c = 11.1827 (7) Å
  • β = 123.342 (4)°
  • V = 1508.41 (16) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.23 mm−1
  • T = 293 (2) K
  • 0.60 × 0.47 × 0.23 mm

Data collection

  • Stoe IPDS2 diffractometer
  • Absorption correction: integration (X-RED32; Stoe & Cie, 2002 [triangle]) T min = 0.876, T max = 0.950
  • 8036 measured reflections
  • 3086 independent reflections
  • 2361 reflections with I > 2σ(I)
  • R int = 0.078

Refinement

  • R[F 2 > 2σ(F 2)] = 0.045
  • wR(F 2) = 0.121
  • S = 0.99
  • 3086 reflections
  • 200 parameters
  • H-atom parameters constrained
  • Δρmax = 0.34 e Å−3
  • Δρmin = −0.41 e Å−3

Data collection: X-AREA (Stoe & Cie, 2002 [triangle]); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808010489/is2289sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808010489/is2289Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS2 diffractometer (purchased under grant F.279 of the University Research Fund).

supplementary crystallographic information

Comment

In a previous paper, we reported the structure of 4-[(2-hydroxy-1-naphthyl)methylideneamino]benzoic acid (Akkurt et al., 2008). The present work is part of an ongoing investigation in the development of anil derivatives. Here, we report the structure of the title compound 2-[(2-hydroxybenzylidene)amino]-3-methoxycarbonyl-3,4,5,6- tetrahydrobenzo[d]thiophene, (I).

In the title compound (I) (Fig. 1), all bond lengths and angles are in normal range (Allen et al., 1987). The thiophene ring is essentially planar, with maximum deviations of 0.006 (1) Å for S1 and 0.006 (3) Å for C17. The cyclohexene ring adopts a half-chair conformation, with the puckering parameters QT = 0.502 (2) Å, θ = 52.1 (2)° and [var phi] = 151.4 (3)° (Cremer & Pople, 1975). The dihedral angle between the thiophene ring and the benzene ring is 29.7 (1)°.

In the molecular structure, the intramolecular O1—H1···O2, and O1—H1···N1 hydrogen bonds form two pseudo-six membered rings [S(6) motifs (Bernstein et al., 1995; Etter, 1990)] and C7—H7···S1 forms a pseudo five membered ring [S(5) motif], thus locking the molecular conformation and eliminating flexibility (Fig. 1 and Table 1). There are also interactions of the C—H···π type [C15—H15A···π (-1 + x, 1/2 - y, -1/2 + z), H15···π = 2.91 Å, C15···π = 3.782 (3) Å] observed between the cyclohexene ring system and the π system of the benzene ring. A view of the packing of the title compound in the unit cell is shown in Fig. 2.

Experimental

A solution of 2-amino-3-methoxycarbonyl-3,4,5,6-tetrahydrobenzo[d]thieophene (2.0 g, 6.35 mmol) in pure ethanol was heated to its boiling temperature, and then 2-hydroxynaphthaldehyde (0.77 g, 6.35 mmol) dissolved in hot ethanol was added to the amine solution and the resulting mixture was then refluxed for 5 h. Cooling the mixture, filtering the precipitates and recrystalization from ethanol gave the pure product (Asiri & Badahdah, 2007). IR (KBr) ν (cm-1); 1697 (C═O), 1604 (C═N), 1443 (C═C), 1323 (C—O) and 1136 (C—N) [yield 98%, m.p. 417 K].

Refinement

The H atoms were positioned geometrically and allowed to ride on their parent atoms, with the C—H distances in the range of 0.93 - 0.97 Å and O—H = 0.82 Å, and Uiso(H) = 1.2Ueq (Caromatic, Cmethylene) and 1.5Ueq (Cmethyl, O).

Figures

Fig. 1.
An ORTEP-3 view of the title compound (I), with the atom-numbering scheme, intramolecular H-bonds and 30% probability displacement ellipsoids.
Fig. 2.
A view of the packing of (I) in the unit cell.

Crystal data

C17H17NO3SF000 = 664
Mr = 315.39Dx = 1.389 Mg m3
Monoclinic, P21/cMo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 10365 reflections
a = 7.6107 (4) Åθ = 1.9–27.2º
b = 21.2154 (9) ŵ = 0.23 mm1
c = 11.1827 (7) ÅT = 293 (2) K
β = 123.342 (4)ºPlate, yellow
V = 1508.41 (16) Å30.60 × 0.47 × 0.23 mm
Z = 4

Data collection

Stoe IPDS2 diffractometer3086 independent reflections
Monochromator: plane graphite2361 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm-1Rint = 0.078
T = 293(2) Kθmax = 26.5º
ω scansθmin = 1.9º
Absorption correction: integration(X-RED32; Stoe & Cie, 2002)h = −9→9
Tmin = 0.876, Tmax = 0.950k = −23→26
8036 measured reflectionsl = −14→13

Refinement

Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.045  w = 1/[σ2(Fo2) + (0.072P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.121(Δ/σ)max < 0.001
S = 0.99Δρmax = 0.34 e Å3
3086 reflectionsΔρmin = −0.40 e Å3
200 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=KFc[1 + 0.001×Fc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.021 (3)
Secondary atom site location: difference Fourier map

Special details

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)

xyzUiso*/Ueq
S10.38087 (8)0.27490 (2)0.37886 (5)0.0508 (2)
O10.7763 (2)0.43178 (7)0.81861 (15)0.0586 (5)
O20.8121 (3)0.28677 (7)0.86144 (15)0.0639 (5)
O30.8298 (3)0.18228 (7)0.85862 (16)0.0662 (5)
N10.6317 (2)0.34975 (7)0.61166 (15)0.0436 (4)
C10.7315 (3)0.45323 (8)0.59125 (18)0.0411 (5)
C20.7924 (3)0.47139 (9)0.7303 (2)0.0450 (5)
C30.8752 (3)0.53085 (10)0.7805 (2)0.0540 (7)
C40.9000 (3)0.57192 (9)0.6957 (3)0.0576 (7)
C50.8421 (3)0.55480 (10)0.5586 (2)0.0577 (7)
C60.7586 (3)0.49630 (9)0.5079 (2)0.0515 (6)
C70.6487 (3)0.39169 (8)0.53568 (19)0.0442 (5)
C80.5536 (3)0.29018 (8)0.55994 (19)0.0425 (5)
C90.6016 (3)0.23555 (8)0.63921 (19)0.0416 (5)
C100.7575 (3)0.23103 (9)0.7957 (2)0.0452 (6)
C110.9685 (4)0.28619 (13)1.0126 (2)0.0705 (8)
C120.4984 (3)0.18131 (8)0.55199 (19)0.0438 (5)
C130.5079 (3)0.11475 (9)0.6026 (2)0.0549 (6)
C140.3347 (3)0.07392 (9)0.4836 (2)0.0572 (7)
C150.3173 (3)0.08294 (10)0.3430 (2)0.0588 (7)
C160.2502 (4)0.14989 (10)0.2891 (2)0.0593 (7)
C170.3767 (3)0.19544 (9)0.41006 (19)0.0457 (6)
H10.725400.398200.777400.0880*
H30.914200.543100.871800.0650*
H40.956400.611700.730600.0690*
H50.859800.582800.502000.0690*
H60.719100.484900.416000.0620*
H70.606300.381900.442400.0530*
H11A1.096300.268201.029900.0850*
H11B0.919000.261401.060200.0850*
H11C0.994700.328501.048700.0850*
H13A0.493000.115300.683300.0660*
H13B0.643900.096600.634600.0660*
H14A0.364000.030000.511500.0690*
H14B0.201300.084500.470700.0690*
H15A0.215200.053500.272600.0700*
H15B0.452200.074300.356300.0700*
H16A0.272100.158300.212900.0710*
H16B0.101700.155100.250900.0710*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
S10.0565 (3)0.0466 (3)0.0366 (3)−0.0026 (2)0.0176 (2)0.0017 (2)
O10.0796 (9)0.0573 (8)0.0470 (8)−0.0121 (7)0.0400 (7)−0.0047 (7)
O20.0802 (10)0.0530 (8)0.0349 (7)−0.0107 (7)0.0166 (7)0.0015 (6)
O30.0735 (9)0.0563 (9)0.0482 (8)0.0110 (7)0.0204 (7)0.0089 (7)
N10.0454 (7)0.0411 (8)0.0389 (8)0.0005 (6)0.0197 (6)0.0023 (6)
C10.0400 (8)0.0424 (9)0.0416 (9)0.0054 (7)0.0228 (7)0.0039 (7)
C20.0482 (9)0.0446 (9)0.0475 (10)0.0020 (7)0.0297 (8)0.0005 (8)
C30.0593 (11)0.0515 (11)0.0558 (12)−0.0004 (9)0.0345 (10)−0.0085 (9)
C40.0577 (11)0.0404 (10)0.0765 (15)−0.0011 (8)0.0381 (11)−0.0031 (10)
C50.0647 (12)0.0488 (11)0.0647 (13)0.0010 (9)0.0388 (11)0.0115 (10)
C60.0574 (10)0.0532 (11)0.0470 (10)0.0011 (9)0.0306 (9)0.0049 (9)
C70.0461 (9)0.0475 (10)0.0373 (9)0.0035 (7)0.0219 (7)0.0011 (8)
C80.0427 (8)0.0432 (9)0.0385 (9)0.0007 (7)0.0204 (7)−0.0008 (8)
C90.0423 (8)0.0429 (9)0.0384 (9)0.0001 (7)0.0215 (7)0.0026 (7)
C100.0448 (9)0.0482 (10)0.0414 (10)−0.0014 (7)0.0230 (8)0.0022 (8)
C110.0794 (15)0.0785 (15)0.0361 (10)−0.0213 (12)0.0207 (10)−0.0009 (10)
C120.0417 (8)0.0435 (9)0.0443 (9)−0.0005 (7)0.0225 (8)0.0007 (8)
C130.0586 (11)0.0464 (10)0.0527 (11)−0.0021 (8)0.0262 (9)0.0054 (9)
C140.0635 (11)0.0457 (10)0.0665 (13)−0.0071 (9)0.0384 (11)−0.0037 (10)
C150.0636 (11)0.0529 (11)0.0619 (13)−0.0089 (9)0.0358 (10)−0.0117 (10)
C160.0657 (12)0.0575 (12)0.0460 (11)−0.0116 (9)0.0251 (10)−0.0100 (9)
C170.0474 (9)0.0446 (10)0.0423 (10)−0.0034 (7)0.0229 (8)−0.0017 (8)

Geometric parameters (Å, °)

S1—C81.7342 (18)C13—C141.527 (3)
S1—C171.725 (2)C14—C151.516 (3)
O1—C21.353 (3)C15—C161.518 (3)
O2—C101.333 (2)C16—C171.503 (3)
O2—C111.436 (2)C3—H30.9300
O3—C101.201 (2)C4—H40.9300
O1—H10.8200C5—H50.9300
N1—C81.381 (2)C6—H60.9300
N1—C71.285 (2)C7—H70.9300
C1—C21.410 (3)C11—H11A0.9600
C1—C71.434 (2)C11—H11B0.9600
C1—C61.399 (3)C11—H11C0.9600
C2—C31.384 (3)C13—H13A0.9700
C3—C41.375 (3)C13—H13B0.9700
C4—C51.391 (3)C14—H14A0.9700
C5—C61.367 (3)C14—H14B0.9700
C8—C91.381 (2)C15—H15A0.9700
C9—C101.482 (3)C15—H15B0.9700
C9—C121.432 (2)C16—H16A0.9700
C12—C171.361 (3)C16—H16B0.9700
C12—C131.508 (3)
S1···C11i3.543 (2)C7···H16Bv3.0900
S1···C10ii3.468 (3)C8···H11Bii2.9900
S1···H72.6900C8···H13.0600
O1···O23.102 (2)C9···H11Bii2.9900
O1···N12.607 (2)C10···H13A2.9800
O2···N12.694 (2)C12···H15B3.0400
O2···O13.102 (2)C17···H14B2.9600
O3···C4iii3.384 (3)H1···O22.5000
O3···C7iv3.359 (3)H1···N11.8800
O3···C132.923 (3)H1···C72.4400
O1···H15Biv2.7200H1···C83.0600
O1···H14Bv2.7300H3···H14Bix2.5200
O2···H12.5000H4···O3vii2.7700
O3···H13A2.6300H4···H13Bvii2.5700
O3···H13B2.7700H5···O3vii2.9000
O3···H11B2.5800H5···H16Ax2.5900
O3···H4iii2.7700H6···H72.4200
O3···H5iii2.9000H7···S12.6900
O3···H11A2.6100H7···H62.4200
O3···H7iv2.7200H7···O3ii2.7200
N1···O12.607 (2)H7···H13Aii2.5300
N1···O22.694 (2)H11A···O32.6100
N1···H11.8800H11B···O32.5800
C1···C1vi3.552 (3)H11B···C8iv2.9900
C1···C6vi3.427 (3)H11B···C9iv2.9900
C2···C6vi3.588 (3)H13A···O32.6300
C4···C7vi3.585 (4)H13A···C102.9800
C4···O3vii3.384 (3)H13A···H7iv2.5300
C5···C7vi3.468 (4)H13B···O32.7700
C6···C2vi3.588 (3)H13B···C4iii2.9500
C6···C1vi3.427 (3)H13B···H4iii2.5700
C7···O3ii3.359 (3)H14A···H14Axi2.5600
C7···C5vi3.468 (4)H14B···C172.9600
C7···C4vi3.585 (4)H14B···H3xii2.5200
C10···S1iv3.468 (3)H14B···O1xiii2.7300
C11···S1viii3.543 (2)H14B···C2xiii3.0200
C13···O32.923 (3)H15A···C1xiii3.0800
C1···H15Av3.0800H15A···C2xiii3.0300
C2···H15Av3.0300H15B···C123.0400
C2···H14Bv3.0200H15B···O1ii2.7200
C4···H13Bvii2.9500H16A···H5xiv2.5900
C7···H12.4400H16B···C7xiii3.0900
C8—S1—C1791.89 (9)C4—C3—H3120.00
C10—O2—C11116.56 (17)C3—C4—H4119.00
C2—O1—H1109.00C5—C4—H4120.00
C7—N1—C8122.23 (16)C4—C5—H5120.00
C2—C1—C7121.75 (18)C6—C5—H5120.00
C6—C1—C7119.76 (17)C1—C6—H6119.00
C2—C1—C6118.47 (17)C5—C6—H6119.00
O1—C2—C1121.91 (17)N1—C7—H7119.00
O1—C2—C3118.30 (17)C1—C7—H7119.00
C1—C2—C3119.79 (19)O2—C11—H11A109.00
C2—C3—C4120.16 (19)O2—C11—H11B109.00
C3—C4—C5121.0 (2)O2—C11—H11C109.00
C4—C5—C6119.2 (2)H11A—C11—H11B109.00
C1—C6—C5121.44 (18)H11A—C11—H11C110.00
N1—C7—C1121.58 (17)H11B—C11—H11C109.00
S1—C8—N1122.39 (13)C12—C13—H13A109.00
N1—C8—C9126.74 (16)C12—C13—H13B109.00
S1—C8—C9110.86 (13)C14—C13—H13A109.00
C8—C9—C10124.74 (17)C14—C13—H13B109.00
C10—C9—C12122.39 (16)H13A—C13—H13B108.00
C8—C9—C12112.63 (16)C13—C14—H14A109.00
O2—C10—C9113.48 (16)C13—C14—H14B109.00
O3—C10—C9124.00 (17)C15—C14—H14A109.00
O2—C10—O3122.52 (18)C15—C14—H14B109.00
C9—C12—C17112.61 (16)H14A—C14—H14B108.00
C13—C12—C17120.37 (16)C14—C15—H15A110.00
C9—C12—C13126.99 (16)C14—C15—H15B110.00
C12—C13—C14111.34 (16)C16—C15—H15A110.00
C13—C14—C15111.96 (19)C16—C15—H15B110.00
C14—C15—C16110.40 (18)H15A—C15—H15B108.00
C15—C16—C17109.58 (16)C15—C16—H16A110.00
S1—C17—C16121.34 (14)C15—C16—H16B110.00
C12—C17—C16126.65 (17)C17—C16—H16A110.00
S1—C17—C12112.01 (14)C17—C16—H16B110.00
C2—C3—H3120.00H16A—C16—H16B108.00
C17—S1—C8—C9−0.8 (2)N1—C8—C9—C10−3.6 (4)
C17—S1—C8—N1177.8 (2)S1—C8—C9—C10174.9 (2)
C8—S1—C17—C121.0 (2)N1—C8—C9—C12−178.1 (2)
C8—S1—C17—C16−178.8 (2)C8—C9—C12—C13−177.4 (2)
C11—O2—C10—C9−177.8 (2)C8—C9—C12—C170.4 (3)
C11—O2—C10—O31.9 (4)C12—C9—C10—O310.0 (4)
C7—N1—C8—C9152.2 (3)C8—C9—C10—O215.7 (4)
C7—N1—C8—S1−26.2 (3)C8—C9—C10—O3−164.0 (3)
C8—N1—C7—C1−179.6 (2)C12—C9—C10—O2−170.3 (2)
C2—C1—C6—C50.1 (4)C10—C9—C12—C137.9 (4)
C7—C1—C2—O10.1 (4)C10—C9—C12—C17−174.3 (2)
C6—C1—C7—N1176.4 (2)C9—C12—C13—C14164.9 (2)
C7—C1—C2—C3178.8 (2)C9—C12—C17—C16178.9 (3)
C2—C1—C7—N1−1.9 (4)C17—C12—C13—C14−12.7 (3)
C6—C1—C2—O1−178.2 (2)C9—C12—C17—S1−1.0 (3)
C7—C1—C6—C5−178.3 (2)C13—C12—C17—C16−3.2 (4)
C6—C1—C2—C30.5 (4)C13—C12—C17—S1177.03 (19)
C1—C2—C3—C4−0.6 (4)C12—C13—C14—C1545.8 (3)
O1—C2—C3—C4178.1 (2)C13—C14—C15—C16−64.5 (3)
C2—C3—C4—C50.3 (4)C14—C15—C16—C1745.7 (3)
C3—C4—C5—C60.3 (4)C15—C16—C17—C12−13.8 (4)
C4—C5—C6—C1−0.4 (4)C15—C16—C17—S1166.03 (19)
S1—C8—C9—C120.4 (3)

Symmetry codes: (i) x−1, y, z−1; (ii) x, −y+1/2, z−1/2; (iii) −x+2, y−1/2, −z+3/2; (iv) x, −y+1/2, z+1/2; (v) x+1, −y+1/2, z+1/2; (vi) −x+1, −y+1, −z+1; (vii) −x+2, y+1/2, −z+3/2; (viii) x+1, y, z+1; (ix) −x+1, y+1/2, −z+3/2; (x) −x+1, y+1/2, −z+1/2; (xi) −x+1, −y, −z+1; (xii) −x+1, y−1/2, −z+3/2; (xiii) x−1, −y+1/2, z−1/2; (xiv) −x+1, y−1/2, −z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1···O20.822.503.102 (2)132
O1—H1···N10.821.882.607 (2)146
C7—H7···S10.932.693.0725 (19)105
C15—H15A···Cgxiii0.972.923.782 (3)150

Symmetry codes: (xiii) x−1, −y+1/2, z−1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IS2289).

References

  • Akkurt, M., Yıldırım, S. Ö., Asiri, A. M. & McKee, V. (2008). Acta Cryst. E64, o682. [PMC free article] [PubMed]
  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Asiri, A. M. & Badahdah, K. O. (2007). Molecules, 12, 1796-1804. [PubMed]
  • Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl.34, 1555–1573.
  • Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc.97, 1354–1358.
  • Etter, M. C. (1990). Acc. Chem. Res.23, 120–126.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Stoe & Cie (2002). X-AREA and X-RED32 Stoe & Cie, Darmstadt, Germany.

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