2-({[4-(1,3-Benzothia­zol-2-yl)phen­yl]amino}methyl)­phenol

Kim Potgieter; Thomas Gerber; Eric Hosten; Richard Betz

doi:10.1107/S1600536811051580

. 2011 Dec 3;68(Pt 1):o27. doi: 10.1107/S1600536811051580

2-({[4-(1,3-Benzothiazol-2-yl)phenyl]amino}methyl)phenol

Kim Potgieter ^a, Thomas Gerber ^a, Eric Hosten ^a, Richard Betz ^a,^*

PMCID: PMC3254391 PMID: 22259532

Abstract

In the title compound, C₂₀H₁₆N₂OS, the aniline substituent essentially coplanar with the benzothiazole moiety (with an r.m.s. deviation of all fitted non-H atoms of 0.0612 Å). The phenol group is almost perpendicular to the benzothiazolylaniline group, with an interplanar angle of 88.36 (2)°. In the crystal, molecules aggregate as centrosymmetric dimers by pairs of O—H⋯N hydrogen bonds. C—H⋯O contacts and N—H⋯π(arene) interactions also occur.

Related literature

For general information about rhenium-supported radio-pharmaceuticals, see: Gerber et al. (2011 ▶). For the crystal structure of 4-(1,3-benzothiazol-2-yl)-N-(2-pyridylmethyl)aniline monohydrate, see: Su et al. (2009 ▶). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₂₀H₁₆N₂OS
M _r = 332.41
Monoclinic,
a = 13.3260 (4) Å
b = 5.7940 (1) Å
c = 24.2246 (6) Å
β = 121.546 (1)°
V = 1593.99 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.21 mm⁻¹
T = 200 K
0.44 × 0.17 × 0.11 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.929, T _max = 1.000
15126 measured reflections
3953 independent reflections
3272 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.092
S = 1.03
3953 reflections
221 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811051580/gg2063sup1.cif

e-68-00o27-sup1.cif^{(24.3KB, cif)}

Supplementary material file. DOI: 10.1107/S1600536811051580/gg2063Isup2.cdx

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811051580/gg2063Isup3.hkl

e-68-00o27-Isup3.hkl^{(193.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811051580/gg2063Isup4.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg is the centroid of the C31–C36 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1ⁱ	0.82	1.95	2.7459 (14)	164
C26—H26⋯O1ⁱ	0.95	2.48	3.3645 (16)	156
N2—H72⋯Cgⁱⁱ	0.82 (2)	2.61 (2)	3.4024 (14)	163.0 (19)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank Mr Jason Kopp for helpful discussions.

supplementary crystallographic information

Comment

In our continuous efforts to create new radio-pharmaceuticals (Gerber et al., 2011), we attempted the coordination reaction of a potentially multidentate ligand towards a rhenium precursor upon which a crystalline reaction product was obtained. The crystal structure analysis showed the presence of the free ligand only whose molecular and crystal structure has not been reported to date. The structure of 4-(1,3-benzothiazol-2-yl)-N-(2-pyridylmethyl) aniline monohydrate is noted in the literature (Su et al., 2009).

The benzothiazolyl system and the attached aniline system are nearly co-planar (r.m.s. of all fitted non-hydrogen atoms including the nitrogen bound methylene group = 0.0612 Å). The phenolic substituent, however, adopts a nearly perpendicular orientation with respect to the rest of the molecule, with an interplanar angle of 88.36 (2)° between the two least-squares planes defined by both moieties (Fig. 1).

In the crystal, classical hydrogen bonds of the O–H···N type as well as C–H···O contacts (whose range lies by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating) are observed. The latter are supported by one of the hydrogen atoms of the central phenyl ring. In total, the molecules are connected to centrosymmetric dimers by these two interactions. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for these contacts is R²₂(18)R²₂(24) on the unitary level. The nitrogen-bonded hydrogen atom forms a hydrogen bond to the aromatic system of the phenolic moiety, connecting the molecules to chains along the crystallographic b axis. Metrical parameters about these contacts as well as information about their symmetry is listed in Table 1. The shortest intercentroid distance between two aromatic systems was measured at 4.6019 (10) Å and is apparent between the phenyl unit of the benzothiazole moiety and the central C₆ aromatic ring (Fig 2.)

The packing of the title compound in the crystal structure is shown in Figure 3.

Experimental

A mixture of 2.00 g of 4-aminobenzoic acid and 1.33 g of 2-aminothiophenol was added to hot polyphosphoric acid. The stirring solution was heated to 220 °C for four hours. The reaction solution was cooled to room temperature and poured into a 10% K₂CO₃ solution. The yellow precipitate which formed was filtered and dried under vacuum, yielding 4-(benzo[d]thiazol-2-yl)benzenamine. A solution of 1.0 g of this product dissolved in 25 cm³ of methanol was added to a 25 cm³ methanol solution of 2-hydroxybenzaldehyde (0.4 g). The solution was refluxed for three hours after which it was cooled to room temperature and stirred overnight. An excess of NaBH₄ (2.0 g) was added in portions with stirring and the mixture was left to stir at room temperature overnight. The solvent was removed by evaporation and 50 cm³ of water was added. HCl was added to adjust the pH to 6, resulting in the formation of a light yellow precipitate which was filtered and dried under vacuum. Crystals suitable for the X-ray diffraction study were obtained upon the attempted synthesis of a rhenium coordination compound in ethanol.