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Acta Crystallogr Sect E Struct Rep Online. 2010 August 1; 66(Pt 8): o2143.
Published online 2010 July 31. doi:  10.1107/S1600536810029442
PMCID: PMC3007372

Ethyl 2-[4-(1,3-benzothiazol-2-yl)­anilino]acetate

Abstract

In the title compound, C17H16N2O2S, the dihedral angle between the benzothia­zole ring system and the benzene ring is 1.20 (2)°. The substituted amino substituent is in an extended conformation with an N—C—C—O torsion angle of 179.4 (3)°. In the crystal structure, pairs of mol­ecules are connected by inter­molecular N—H(...)O and weak C—H(...)O hydrogen bonds, forming centrosymmetric dimers.

Related literature

For background to thio­flavin T (ThT), a benzothia­zole dye that exhibits enhanced fluorescence upon binding to amyloid fibrils, and its derivatives, see: Kung et al. (2001 [triangle]); Qu et al. (2007 [triangle]); Zhang & Zhao (2009 [triangle]). For the synthesis, see: Stephenson et al. (2007 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o2143-scheme1.jpg

Experimental

Crystal data

  • C17H16N2O2S
  • M r = 312.38
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2143-efi1.jpg
  • a = 5.6303 (1) Å
  • b = 26.1604 (5) Å
  • c = 10.5989 (2) Å
  • β = 98.294 (1)°
  • V = 1544.79 (5) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.22 mm−1
  • T = 298 K
  • 0.36 × 0.24 × 0.21 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.926, T max = 0.956
  • 11631 measured reflections
  • 3808 independent reflections
  • 3015 reflections with I > 2σ(I)
  • R int = 0.076

Refinement

  • R[F 2 > 2σ(F 2)] = 0.058
  • wR(F 2) = 0.145
  • S = 1.07
  • 3808 reflections
  • 203 parameters
  • 1 restraint
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.39 e Å−3
  • Δρmin = −0.30 e Å−3

Data collection: SMART (Bruker, 2007 [triangle]); cell refinement: SAINT-Plus (Bruker, 2007 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810029442/lh5087sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810029442/lh5087Isup2.hkl

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

supplementary crystallographic information

Comment

Thioflavin T (ThT) is a benzothiazole dye that exhibits enhanced fluorescence upon binding to amyloid fibrils and is commonly used to diagnose amyloid fibrils, both ex vivo and in vitro. Many derivatives of thioflavin T have been synthesized and evaluated recently (Kung et al., 2001; Qu et al., 2007; Zhang, et al., 2009). We are interested in developing fluorescent probes that are expected to bind to hydrophobic sites in proteins. With this in mind, the title compound, (I), was synthesized and we reported the crystal structure herein.

In the molecular structure (Fig. 1), the dihedral angle between the benzothiazole ring system and the benzene ring is 1.20 (2)°. The substituted amino substituent is in an extended conformation with an N—C—C—O torsion angle of 179.4 (3)°. In the crystal structure, pairs of molecules are connected by intermolecular N—H···O and weak C-H···O hydrogen bonds to form centrosymmetric dimers (Fig. 2).

Experimental

Compound (I) was synthesized according to the method described by Stephenson et al. (2007). Pale yellow single crystals suitable for an X-ray diffraction study were obtained by slow evaporation of an methanol solution.

Refinement

All H atoms were placed in idealized positions [CH(methyl)=0.96 Å, 0.97Å (methylene) and 0.93 Å (aromatic),with Uiso(H)= 1.5Ueq(methyl C) 1.2Ueq(other C). N-bounded hydrogen atom was found from the difference map and refined with the restraint of N—H = 0.86 (1)Å and Uiso(H) = 1.2 Ueq(N).

Figures

Fig. 1.
The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level.
Fig. 2.
Part of the crystal structure of (I) showing hydrogen bonds as dashed lines.

Crystal data

C17H16N2O2SF(000) = 656
Mr = 312.38Dx = 1.343 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 3368 reflections
a = 5.6303 (1) Åθ = 2.5–26.1°
b = 26.1604 (5) ŵ = 0.22 mm1
c = 10.5989 (2) ÅT = 298 K
β = 98.294 (1)°Block, pale-yellow
V = 1544.79 (5) Å30.36 × 0.24 × 0.21 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer3808 independent reflections
Radiation source: fine-focus sealed tube3015 reflections with I > 2σ(I)
graphiteRint = 0.076
[var phi] and ω scansθmax = 28.3°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −7→6
Tmin = 0.926, Tmax = 0.956k = −34→34
11631 measured reflectionsl = −10→14

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.058Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.145H atoms treated by a mixture of independent and constrained refinement
S = 1.07w = 1/[σ2(Fo2) + (0.0584P)2 + 0.2785P] where P = (Fo2 + 2Fc2)/3
3808 reflections(Δ/σ)max < 0.001
203 parametersΔρmax = 0.39 e Å3
1 restraintΔρmin = −0.30 e Å3

Special details

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)

xyzUiso*/Ueq
C10.4095 (4)0.16282 (7)1.27189 (19)0.0459 (4)
C20.5567 (4)0.18305 (9)1.3771 (2)0.0584 (6)
H20.70500.16851.40670.070*
C30.4757 (5)0.22514 (9)1.4357 (2)0.0624 (6)
H30.57120.23971.50540.075*
C40.2521 (5)0.24629 (8)1.3919 (2)0.0614 (6)
H40.20070.27481.43300.074*
C50.1066 (4)0.22608 (8)1.2896 (2)0.0552 (5)
H5−0.04260.24061.26180.066*
C60.1840 (3)0.18348 (7)1.22724 (19)0.0429 (4)
C70.1778 (3)0.12057 (7)1.08723 (18)0.0388 (4)
C80.0933 (3)0.08695 (7)0.98019 (17)0.0383 (4)
C90.2312 (3)0.04687 (7)0.94479 (19)0.0459 (5)
H90.38150.04080.99150.055*
C100.1514 (3)0.01576 (7)0.84224 (19)0.0461 (5)
H100.2472−0.01100.82140.055*
C11−0.0722 (3)0.02423 (7)0.76967 (18)0.0404 (4)
C12−0.2144 (3)0.06424 (7)0.80651 (19)0.0444 (4)
H12−0.36570.07010.76080.053*
C13−0.1326 (3)0.09459 (7)0.90894 (19)0.0440 (4)
H13−0.22950.12090.93150.053*
C14−0.0362 (3)−0.04854 (7)0.62537 (19)0.0448 (4)
H14A−0.0175−0.07340.69410.054*
H14B0.1222−0.03940.60680.054*
C15−0.1818 (3)−0.07146 (7)0.50852 (19)0.0439 (4)
C16−0.1958 (4)−0.13779 (8)0.3566 (2)0.0503 (5)
H16A−0.2157−0.11380.28600.060*
H16B−0.3530−0.15020.36940.060*
C17−0.0407 (4)−0.18121 (8)0.3288 (2)0.0621 (6)
H17A0.1178−0.16880.32280.093*
H17B−0.1070−0.19680.24950.093*
H17C−0.0329−0.20600.39610.093*
N10.0567 (3)0.15892 (6)1.12304 (15)0.0441 (4)
N2−0.1552 (3)−0.00386 (7)0.66362 (18)0.0538 (5)
H2A−0.294 (2)0.0014 (8)0.622 (2)0.065*
O1−0.0780 (3)−0.11295 (5)0.47181 (14)0.0506 (4)
O2−0.3671 (3)−0.05410 (6)0.45639 (16)0.0655 (5)
S10.46125 (9)0.11103 (2)1.17793 (6)0.05496 (19)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0511 (11)0.0454 (10)0.0419 (11)−0.0041 (8)0.0096 (9)−0.0032 (8)
C20.0616 (13)0.0634 (13)0.0489 (13)−0.0079 (10)0.0030 (10)−0.0080 (10)
C30.0821 (16)0.0581 (13)0.0474 (13)−0.0199 (12)0.0104 (11)−0.0098 (10)
C40.0927 (17)0.0426 (11)0.0531 (13)−0.0085 (11)0.0250 (13)−0.0090 (10)
C50.0695 (13)0.0426 (11)0.0554 (13)0.0028 (9)0.0160 (11)−0.0009 (10)
C60.0519 (11)0.0375 (9)0.0409 (10)−0.0028 (8)0.0121 (8)0.0019 (8)
C70.0396 (9)0.0392 (9)0.0374 (10)0.0001 (7)0.0049 (7)0.0034 (7)
C80.0394 (9)0.0394 (9)0.0362 (10)−0.0009 (7)0.0056 (7)0.0017 (7)
C90.0423 (10)0.0463 (10)0.0463 (11)0.0070 (8)−0.0032 (8)−0.0016 (9)
C100.0485 (10)0.0402 (10)0.0476 (12)0.0084 (8)0.0004 (9)−0.0051 (8)
C110.0428 (9)0.0380 (9)0.0399 (10)−0.0026 (7)0.0038 (8)0.0003 (8)
C120.0364 (9)0.0493 (10)0.0459 (11)0.0039 (7)0.0011 (8)−0.0025 (9)
C130.0422 (10)0.0439 (10)0.0463 (11)0.0056 (8)0.0073 (8)−0.0023 (8)
C140.0470 (10)0.0422 (10)0.0432 (11)0.0000 (8)0.0001 (8)−0.0022 (8)
C150.0479 (10)0.0413 (10)0.0421 (11)−0.0022 (8)0.0051 (8)−0.0011 (8)
C160.0563 (12)0.0487 (11)0.0455 (12)−0.0081 (9)0.0052 (9)−0.0084 (9)
C170.0786 (15)0.0489 (12)0.0609 (15)−0.0035 (11)0.0173 (12)−0.0134 (11)
N10.0489 (9)0.0400 (8)0.0430 (9)0.0032 (7)0.0056 (7)0.0004 (7)
N20.0507 (10)0.0511 (10)0.0544 (11)0.0084 (8)−0.0106 (8)−0.0151 (8)
O10.0578 (8)0.0440 (7)0.0478 (9)0.0042 (6)0.0004 (6)−0.0084 (6)
O20.0596 (9)0.0661 (10)0.0640 (11)0.0166 (7)−0.0141 (8)−0.0198 (8)
S10.0455 (3)0.0623 (3)0.0537 (4)0.0105 (2)−0.0047 (2)−0.0168 (3)

Geometric parameters (Å, °)

C1—C21.394 (3)C10—H100.9300
C1—C61.398 (3)C11—N21.367 (2)
C1—S11.731 (2)C11—C121.407 (3)
C2—C31.374 (3)C12—C131.370 (3)
C2—H20.9300C12—H120.9300
C3—C41.392 (4)C13—H130.9300
C3—H30.9300C14—N21.434 (2)
C4—C51.367 (3)C14—C151.507 (3)
C4—H40.9300C14—H14A0.9700
C5—C61.397 (3)C14—H14B0.9700
C5—H50.9300C15—O21.197 (2)
C6—N11.385 (2)C15—O11.318 (2)
C7—N11.300 (2)C16—O11.456 (2)
C7—C81.460 (3)C16—C171.488 (3)
C7—S11.7579 (18)C16—H16A0.9700
C8—C91.388 (3)C16—H16B0.9700
C8—C131.397 (3)C17—H17A0.9600
C9—C101.380 (3)C17—H17B0.9600
C9—H90.9300C17—H17C0.9600
C10—C111.395 (3)N2—H2A0.853 (9)
C2—C1—C6122.01 (19)C13—C12—C11120.77 (17)
C2—C1—S1128.85 (17)C13—C12—H12119.6
C6—C1—S1109.13 (14)C11—C12—H12119.6
C3—C2—C1117.9 (2)C12—C13—C8121.42 (17)
C3—C2—H2121.1C12—C13—H13119.3
C1—C2—H2121.1C8—C13—H13119.3
C2—C3—C4120.7 (2)N2—C14—C15109.62 (15)
C2—C3—H3119.6N2—C14—H14A109.7
C4—C3—H3119.6C15—C14—H14A109.7
C5—C4—C3121.4 (2)N2—C14—H14B109.7
C5—C4—H4119.3C15—C14—H14B109.7
C3—C4—H4119.3H14A—C14—H14B108.2
C4—C5—C6119.4 (2)O2—C15—O1124.76 (18)
C4—C5—H5120.3O2—C15—C14124.23 (18)
C6—C5—H5120.3O1—C15—C14111.01 (16)
N1—C6—C5125.91 (19)O1—C16—C17107.31 (17)
N1—C6—C1115.52 (16)O1—C16—H16A110.3
C5—C6—C1118.57 (19)C17—C16—H16A110.3
N1—C7—C8124.46 (16)O1—C16—H16B110.3
N1—C7—S1115.02 (14)C17—C16—H16B110.3
C8—C7—S1120.52 (13)H16A—C16—H16B108.5
C9—C8—C13117.59 (17)C16—C17—H17A109.5
C9—C8—C7122.20 (16)C16—C17—H17B109.5
C13—C8—C7120.21 (16)H17A—C17—H17B109.5
C10—C9—C8121.81 (17)C16—C17—H17C109.5
C10—C9—H9119.1H17A—C17—H17C109.5
C8—C9—H9119.1H17B—C17—H17C109.5
C9—C10—C11120.39 (17)C7—N1—C6110.97 (16)
C9—C10—H10119.8C11—N2—C14123.52 (16)
C11—C10—H10119.8C11—N2—H2A121.2 (16)
N2—C11—C10122.80 (17)C14—N2—H2A114.6 (16)
N2—C11—C12119.18 (16)C15—O1—C16116.58 (16)
C10—C11—C12118.00 (17)C1—S1—C789.35 (9)
C6—C1—C2—C3−1.2 (3)C10—C11—C12—C131.5 (3)
S1—C1—C2—C3179.40 (17)C11—C12—C13—C8−0.1 (3)
C1—C2—C3—C40.8 (3)C9—C8—C13—C12−1.0 (3)
C2—C3—C4—C5−0.1 (4)C7—C8—C13—C12178.72 (17)
C3—C4—C5—C6−0.3 (3)N2—C14—C15—O20.6 (3)
C4—C5—C6—N1179.89 (19)N2—C14—C15—O1−179.36 (16)
C4—C5—C6—C10.0 (3)C8—C7—N1—C6180.00 (16)
C2—C1—C6—N1−179.10 (18)S1—C7—N1—C6−0.2 (2)
S1—C1—C6—N10.4 (2)C5—C6—N1—C7179.97 (18)
C2—C1—C6—C50.8 (3)C1—C6—N1—C7−0.1 (2)
S1—C1—C6—C5−179.68 (15)C10—C11—N2—C148.1 (3)
N1—C7—C8—C9179.13 (18)C12—C11—N2—C14−173.43 (19)
S1—C7—C8—C9−0.6 (3)C15—C14—N2—C11177.26 (18)
N1—C7—C8—C13−0.6 (3)O2—C15—O1—C162.3 (3)
S1—C7—C8—C13179.68 (14)C14—C15—O1—C16−177.66 (16)
C13—C8—C9—C100.7 (3)C17—C16—O1—C15176.34 (17)
C7—C8—C9—C10−178.98 (18)C2—C1—S1—C7179.0 (2)
C8—C9—C10—C110.6 (3)C6—C1—S1—C7−0.41 (15)
C9—C10—C11—N2176.82 (19)N1—C7—S1—C10.39 (15)
C9—C10—C11—C12−1.7 (3)C8—C7—S1—C1−179.83 (16)
N2—C11—C12—C13−177.13 (19)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C12—H12···O2i0.932.603.390 (2)144
N2—H2A···O2i0.85 (1)2.40 (1)3.188 (2)154 (2)

Symmetry codes: (i) −x−1, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5087).

References

  • Bruker (2007). SAINT-Plus and SMART Bruker AXS Inc., Madison, Wisconsin, USA.
  • Kung, H. F., Lee, C.-W., Zhuang, Z.-P., Kung, M.-P., Hou, C. & Plssl, K. (2001). J. Am. Chem. Soc.123, 12740–12741. [PubMed]
  • Qu, W., Kung, M.-P., Hou, C., Oya, S. & Kung, H. F. (2007). J. Med. Chem.50, 3380–3387. [PMC free article] [PubMed]
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
  • Stephenson, K. A., Chandra, R., Zhuang, Z.-P., Hou, C., Oya, S., Kung, M.-P. & Kung, H. F. (2007). Bioconjugate Chem.18, 238–246. [PMC free article] [PubMed]
  • Zhang, Y. & Zhao, B. (2009). Acta Cryst. E65, o2762. [PMC free article] [PubMed]

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