Crystal structure of 2-tert-butyl-1,3-thia­zolo[4,5-b]pyridine

El-Hiti, G.A.; Smith, K.; Hegazy, A.S.; Masmali, A.M.; Kariuki, B.M.

doi:10.1107/S160053681401633X

organic compounds

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Volume 70| Part 9| September 2014| Page o932

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Crystal structure of 2-tert-butyl-1,3-thiazolo[4,5-b]pyridine

Gamal A. El-Hiti,^a ^* Keith Smith,^b Amany S. Hegazy,^b Ali M. Masmali ^a and Benson M. Kariuki ^b ^*

^aCornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, PO Box 10219, Riyadh 11433, Saudi Arabia, and ^bSchool of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales
^*Correspondence e-mail: gelhiti@ksu.edu.sa, kariukib@cardiff.ac.uk

Edited by G. Smith, Queensland University of Technology, Australia (Received 2 July 2014; accepted 14 July 2014; online 1 August 2014)

The title compound, C₁₀H₁₂N₂S, does not contain any strong hydrogen-bond donors but two long C—H⋯N contacts are observed in the crystal structure, with the most linear interaction linking molecules along [010]. The ellipsoids of the tert-butyl group indicate large librational motion.

Keywords: crystal structure; C—H⋯N contacts; 1,3-thiazolo[4,5-b]pyridine.

CCDC reference: 1013859

1. Related literature

For the synthesis of substituted thiazolopyridines, see: Smith et al. (1994 , 1995 ); El-Hiti (2003 ); Johnson et al. (2006 ); Rao et al. (2009 ); Sahasrabudhe et al. (2009 ); Lee et al. (2010 ); Chaban et al. (2013 ). For the crystal structure of a related compound, see: Yu et al. (2007 ).

2. Experimental

2.1. Crystal data

C₁₀H₁₂N₂S
M_r = 192.28
Orthorhombic, P 2₁ 2₁ 2₁
a = 9.4606 (3) Å
b = 9.7999 (3) Å
c = 11.1155 (4) Å
V = 1030.55 (6) Å³
Z = 4
Cu Kα radiation
μ = 2.42 mm⁻¹
T = 296 K
0.40 × 0.29 × 0.14 mm

2.2. Data collection

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014 ) T_min = 0.721, T_max = 1.000
3395 measured reflections
1996 independent reflections
1951 reflections with I > 2σ(I)
R_int = 0.016

2.3. Refinement

R[F² > 2σ(F²)] = 0.033
wR(F²) = 0.090
S = 1.12
1996 reflections
121 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.22 e Å⁻³
Absolute structure: Flack x determined using 791 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013 ).
Absolute structure parameter: 0.027 (7)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯N1ⁱ	0.93	2.81	3.564 (3)	138
C6—H6⋯N1ⁱⁱ	0.93	2.72	3.620 (3)	164
Symmetry codes: (i) $[-x+{\script{3\over 2}}, -y+1, z+{\script{1\over 2}}]$ ; (ii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: CHEMDRAW ultra (Cambridge Soft, 2001 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

CCDC reference: 1013859

Crystal structure: contains datablocks I, shelx. DOI: 10.1107/S160053681401633X/zs2307sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681401633X/zs2307Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681401633X/zs2307Isup3.cml

checkCIF report

Structural commentary top

Various methods have been reported for the synthesis of substituted thiazolopyridines (Smith et al., 1994, 1995; El-Hiti, 2003; Johnson et al., 2006; Rao et al., 2009; Sahasrabudhe et al., 2009; Lee et al., 2010; Chaban et al., 2013). In a continuation of our research focused on new synthetic routes towards substituted heterocycles we have synthesized the title compound 2-tert-butylthiazolo[4,5-b]pyridine in high yield (Smith et al., 1995; El-Hiti, 2003) and now report its X-ray crystal structure. The X-ray structure for a related compound has been reported previously (Yu et al., 2007). In the title compound (Fig. 1), the ellipsoids of the methyl groups of the tert-butyl group are large which is consistent with librational motion of the group. Assumption of a disordered model did not show significant improvement in the refinement. The molecule does not contain strong hydrogen bond donors. In the crystal, two long C—H···N contacts are observed, the most linear of which links the molecules in chains along [010] (Fig. 2).

Synthesis and crystallization top

2-tert-Butylthiazolo[4,5-b]pyridine was obtained in 97% yield from acid hydrolysis of 3-(diisopropylaminothiocarbonylthio)-2-(pivalamido)pyridine under reflux (Smith et al., 1995). The compound may also be synthesized in 66% yield from reaction of 3-(diisopropylaminothiocarbonylthio)-2-aminopyridine with 2,2-dimethylpropionic acid in the presence of phosphorus oxychloride under reflux (El-Hiti, 2003). Crystallization from a mixture of ethyl acetate and diethyl ether (1:3 by volume) gave the title compound as colourless crystals. The NMR and low and high resolution mass spectra for the title compound were consistent with those previously reported (Smith et al., 1995).

Refinement top

Crystal data, data collection and structure refinement details are summarized in the crystal data table. The hydrogen atoms were positioned geometrically and refined using a riding model with U_iso(H) = 1.2 times U_eq for the atom to which they are bonded in the case of aromatic rings, NH and CH₂ groups and 1.5 times U_eq for the methyl hydrogens. Crystal data, data collection and structure refinement details are summarized in Table 1. The Flack parameter (Parsons et al., 2013) was 0.027 (7) but is not of any structural relevance with this compound.

Related literature top

For related structures, see: Smith et al. (1994, 1995); El-Hiti (2003); Johnson et al. (2006); Rao et al. (2009); Sahasrabudhe et al. (2009); Lee et al. (2010); Chaban et al. (2013). For the X-ray crystal structure for a related compound, see: Yu et al. (2007).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014; data reduction: CrysAlis PRO (Agilent, 2014; program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008, 2013); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008, 2013); molecular graphics: CHEMDRAW ultra (Cambridge Soft, 2001); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. A molecule of the title compound showing atom labels and 50% probability displacement ellipsoids for non-H atoms.
	Fig. 2. Crystal structure packing with the long linear C—H···N contacts shown as dashed lines.

2-tert-Butyl-1,3-thiazolo[4,5-b]pyridine top

Crystal data top

C₁₀H₁₂N₂S	D_x = 1.239 Mg m⁻³
M_r = 192.28	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 1951 reflections
a = 9.4606 (3) Å	θ = 6.0–73.4°
b = 9.7999 (3) Å	µ = 2.42 mm⁻¹
c = 11.1155 (4) Å	T = 296 K
V = 1030.55 (6) Å³	Plate, colourless
Z = 4	0.40 × 0.29 × 0.14 mm
F(000) = 408

Data collection top

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer	1951 reflections with I > 2σ(I)
Radiation source: SuperNova (Cu) X-ray Source	R_int = 0.016
ω scans	θ_max = 73.4°, θ_min = 6.0°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	h = −7→11
T_min = 0.721, T_max = 1.000	k = −11→12
3395 measured reflections	l = −13→10
1996 independent reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.033	w = 1/[σ²(F_o²) + (0.0513P)² + 0.0815P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.090	(Δ/σ)_max < 0.001
S = 1.12	Δρ_max = 0.16 e Å⁻³
1996 reflections	Δρ_min = −0.22 e Å⁻³
121 parameters	Absolute structure: Flack x determined using 791 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013).
0 restraints	Absolute structure parameter: 0.027 (7)

Crystal data top

C₁₀H₁₂N₂S	V = 1030.55 (6) Å³
M_r = 192.28	Z = 4
Orthorhombic, P2₁2₁2₁	Cu Kα radiation
a = 9.4606 (3) Å	µ = 2.42 mm⁻¹
b = 9.7999 (3) Å	T = 296 K
c = 11.1155 (4) Å	0.40 × 0.29 × 0.14 mm

Data collection top

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer	1996 independent reflections
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	1951 reflections with I > 2σ(I)
T_min = 0.721, T_max = 1.000	R_int = 0.016
3395 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.033	H-atom parameters constrained
wR(F²) = 0.090	Δρ_max = 0.16 e Å⁻³
S = 1.12	Δρ_min = −0.22 e Å⁻³
1996 reflections	Absolute structure: Flack x determined using 791 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013).
121 parameters	Absolute structure parameter: 0.027 (7)
0 restraints

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.8245 (2)	0.2846 (2)	0.37042 (19)	0.0458 (5)
C2	0.6967 (2)	0.4685 (2)	0.33748 (19)	0.0435 (5)
C3	0.7716 (2)	0.5154 (3)	0.4378 (2)	0.0483 (5)
C4	0.7455 (3)	0.6454 (3)	0.4822 (3)	0.0645 (6)
H4	0.7924	0.6789	0.5496	0.077*
C5	0.6470 (3)	0.7218 (3)	0.4218 (3)	0.0677 (7)
H5	0.6260	0.8097	0.4477	0.081*
C6	0.5791 (3)	0.6682 (3)	0.3225 (3)	0.0656 (7)
H6	0.5138	0.7234	0.2833	0.079*
C7	0.8831 (3)	0.1417 (2)	0.3577 (2)	0.0556 (6)
C8	0.8599 (5)	0.0641 (4)	0.4747 (3)	0.0938 (11)
H8A	0.9096	0.1090	0.5387	0.141*
H8B	0.8948	−0.0274	0.4662	0.141*
H8C	0.7608	0.0617	0.4929	0.141*
C9	1.0411 (4)	0.1506 (5)	0.3319 (5)	0.1151 (16)
H9A	1.0560	0.1983	0.2575	0.173*
H9B	1.0798	0.0603	0.3260	0.173*
H9C	1.0871	0.1990	0.3961	0.173*
C10	0.8067 (6)	0.0657 (4)	0.2577 (4)	0.124 (2)
H10A	0.7076	0.0614	0.2758	0.186*
H10B	0.8440	−0.0251	0.2513	0.186*
H10C	0.8203	0.1129	0.1829	0.186*
N1	0.72864 (19)	0.3364 (2)	0.30173 (16)	0.0453 (4)
N2	0.6004 (2)	0.5424 (2)	0.2787 (2)	0.0576 (5)
S1	0.88585 (7)	0.39028 (7)	0.48644 (5)	0.0607 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0431 (10)	0.0571 (12)	0.0371 (10)	0.0007 (10)	−0.0013 (8)	0.0016 (9)
C2	0.0423 (10)	0.0483 (11)	0.0398 (10)	−0.0043 (9)	0.0022 (8)	0.0053 (9)
C3	0.0443 (11)	0.0550 (12)	0.0457 (11)	−0.0048 (9)	0.0022 (9)	−0.0035 (9)
C4	0.0664 (15)	0.0611 (14)	0.0661 (15)	−0.0075 (11)	0.0034 (13)	−0.0160 (13)
C5	0.0707 (17)	0.0500 (13)	0.0823 (19)	−0.0008 (12)	0.0129 (15)	−0.0023 (13)
C6	0.0686 (16)	0.0542 (13)	0.0740 (17)	0.0102 (12)	0.0041 (14)	0.0157 (13)
C7	0.0564 (12)	0.0560 (13)	0.0544 (12)	0.0118 (11)	−0.0010 (11)	0.0012 (10)
C8	0.122 (3)	0.078 (2)	0.081 (2)	0.0248 (19)	0.009 (2)	0.0219 (17)
C9	0.074 (2)	0.097 (3)	0.174 (5)	0.0241 (19)	0.044 (3)	−0.007 (3)
C10	0.187 (5)	0.073 (2)	0.112 (3)	0.052 (3)	−0.072 (3)	−0.034 (2)
N1	0.0468 (9)	0.0492 (9)	0.0401 (9)	0.0001 (8)	−0.0045 (8)	0.0005 (8)
N2	0.0588 (11)	0.0570 (11)	0.0570 (12)	0.0070 (10)	−0.0078 (10)	0.0101 (9)
S1	0.0568 (3)	0.0761 (4)	0.0493 (3)	0.0096 (3)	−0.0161 (3)	−0.0112 (3)

Geometric parameters (Å, º) top

C1—N1	1.290 (3)	C6—H6	0.9300
C1—C7	1.512 (3)	C7—C10	1.521 (4)
C1—S1	1.753 (2)	C7—C8	1.522 (4)
C2—N2	1.335 (3)	C7—C9	1.524 (4)
C2—N1	1.387 (3)	C8—H8A	0.9600
C2—C3	1.399 (3)	C8—H8B	0.9600
C3—C4	1.389 (4)	C8—H8C	0.9600
C3—S1	1.722 (3)	C9—H9A	0.9600
C4—C5	1.371 (4)	C9—H9B	0.9600
C4—H4	0.9300	C9—H9C	0.9600
C5—C6	1.380 (4)	C10—H10A	0.9600
C5—H5	0.9300	C10—H10B	0.9600
C6—N2	1.341 (4)	C10—H10C	0.9600

N1—C1—C7	124.6 (2)	C8—C7—C9	109.3 (3)
N1—C1—S1	115.80 (18)	C7—C8—H8A	109.5
C7—C1—S1	119.64 (17)	C7—C8—H8B	109.5
N2—C2—N1	121.0 (2)	H8A—C8—H8B	109.5
N2—C2—C3	123.9 (2)	C7—C8—H8C	109.5
N1—C2—C3	115.1 (2)	H8A—C8—H8C	109.5
C4—C3—C2	119.7 (2)	H8B—C8—H8C	109.5
C4—C3—S1	130.8 (2)	C7—C9—H9A	109.5
C2—C3—S1	109.55 (18)	C7—C9—H9B	109.5
C5—C4—C3	116.6 (3)	H9A—C9—H9B	109.5
C5—C4—H4	121.7	C7—C9—H9C	109.5
C3—C4—H4	121.7	H9A—C9—H9C	109.5
C4—C5—C6	120.0 (3)	H9B—C9—H9C	109.5
C4—C5—H5	120.0	C7—C10—H10A	109.5
C6—C5—H5	120.0	C7—C10—H10B	109.5
N2—C6—C5	124.8 (3)	H10A—C10—H10B	109.5
N2—C6—H6	117.6	C7—C10—H10C	109.5
C5—C6—H6	117.6	H10A—C10—H10C	109.5
C1—C7—C10	110.3 (2)	H10B—C10—H10C	109.5
C1—C7—C8	109.3 (2)	C1—N1—C2	110.6 (2)
C10—C7—C8	108.1 (3)	C2—N2—C6	115.0 (2)
C1—C7—C9	108.9 (3)	C3—S1—C1	88.96 (11)
C10—C7—C9	110.9 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···N1ⁱ	0.93	2.81	3.564 (3)	138
C6—H6···N1ⁱⁱ	0.93	2.72	3.620 (3)	164

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···N1ⁱ	0.93	2.81	3.564 (3)	138
C6—H6···N1ⁱⁱ	0.93	2.72	3.620 (3)	164

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

Acknowledgements

The authors extend their appreciation to the Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, for funding this research.

References

Agilent (2014). CrysAlis PRO. Agilent Technologies, Yarnton, Oxfordshire, England. Google Scholar
Cambridge Soft (2001). CHEMDRAW Ultra. Cambridge Soft Corporation, Cambridge, Massachusetts, USA. Google Scholar
Chaban, T. I., Ogurtsov, V. V., Chaban, I. G., Klenina, O. V. & Komarytsia, J. D. (2013). Phosphorus Sulfur Silicon Relat. Elem. 188, 1611–1620. Web of Science CrossRef CAS Google Scholar
El-Hiti, G. A. (2003). Monatsh. Chem. 134, 837–841. CAS Google Scholar
Johnson, S. G., Connolly, P. J. & Murray, W. V. (2006). Tetrahedron Lett. 47, 4853–4856. Web of Science CrossRef CAS Google Scholar
Lee, T., Lee, D., Lee, I. Y. & Gong, Y.-D. (2010). J. Combin. Chem. 12, 95–99. Web of Science CrossRef CAS Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CrossRef CAS IUCr Journals Google Scholar
Rao, A. U., Palani, A., Chen, X., Huang, Y., Aslanian, R. G., West, R. E. Jr, Williams, S. M., Wu, R.-L., Hwa, J., Sondey, C. & Lachowicz, J. (2009). Bioorg. Med. Chem. Lett. 19, 6176–6180. Web of Science CrossRef PubMed CAS Google Scholar
Sahasrabudhe, K. P., Estiarte, M. A., Tan, D., Zipfel, S., Cox, M., O'Mahony, D. J. R., Edwards, W. T. & Duncton, M. A. J. (2009). J. Heterocycl. Chem. 46, 1125–1131. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Smith, K., Anderson, D. & Matthews, I. (1995). Sulfur Lett. 18, 79–95. CAS Google Scholar
Smith, K., Lindsay, C. M., Morris, I. K., Matthews, I. & Pritchard, G. J. (1994). Sulfur Lett. 17, 197–216. CAS Google Scholar
Yu, Y.-Q., Wang, Y., Ni, P.-Z. & Lu, T. (2007). Acta Cryst. E63, o968–o969. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar

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CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 9| September 2014| Page o932

doi:10.1107/S160053681401633X

Open

access