2-(5-Bromo­pyridin-3-yl)-5-[3-(4,5,6,7-tetra­hydro­thieno[3,2-c]pyridine-5-ylsulfon­yl)thio­phen-2-yl]-1,3,4-oxa­diazole

Hoong-Kun Fun; Madhukar Hemamalini; Sankappa Rai; A M Isloor; Prakash Shetty

doi:10.1107/S1600536811038529

. 2011 Sep 30;67(Pt 10):o2743–o2744. doi: 10.1107/S1600536811038529

2-(5-Bromopyridin-3-yl)-5-[3-(4,5,6,7-tetrahydrothieno[3,2-c]pyridine-5-ylsulfonyl)thiophen-2-yl]-1,3,4-oxadiazole

Hoong-Kun Fun ^a,^*,^‡, Madhukar Hemamalini ^a, Sankappa Rai ^b, A M Isloor ^c, Prakash Shetty ^d

PMCID: PMC3201536 PMID: 22058804

Abstract

In the title compound, C₁₈H₁₃BrN₄O₃S₃, the tetrahydropyridine ring adopts a half-chair conformation with the central methylene-C atom of the NCH₂CH₂ unit at the flap. The dihedral angles between the tetrahydropyridine ring and the pyridine and two thiophene rings are 69.34 (13) 5.66 (13) and 68.63 (13)°, respectively, while the dihedral angle between the 1,3,4-oxadiazole and tetrahydropyridine rings is 54.76 (13)°. The molecule is stabilized by an intramolecular C—H⋯N interaction. In the crystal, adjacent molecules are connected via bifurcated C—H⋯(N,O) hydrogen bonds, forming a chain along the b axis.

Related literature

For applications of 4,5,6,7-tetrahydrothieno[3,2-c]pyridine derivatives, see: Lopez-Rodriguez et al. (2001 ▶); Roth et al. (1994 ▶); Ying & Rusak (1997 ▶). For ring conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₈H₁₃BrN₄O₃S₃
M _r = 509.41
Monoclinic,
a = 7.0327 (14) Å
b = 7.6488 (15) Å
c = 36.939 (7) Å
β = 91.315 (5)°
V = 1986.5 (7) Å³
Z = 4
Mo Kα radiation
μ = 2.41 mm⁻¹
T = 296 K
0.35 × 0.13 × 0.05 mm

Data collection

Bruker APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.482, T _max = 0.885
22958 measured reflections
7230 independent reflections
4160 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.123
S = 1.02
7230 reflections
262 parameters
H-atom parameters constrained
Δρ_max = 0.76 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811038529/tk2791sup1.cif

e-67-o2743-sup1.cif^{(21.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811038529/tk2791Isup2.hkl

e-67-o2743-Isup2.hkl^{(346.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811038529/tk2791Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7A⋯N2	0.97	2.52	3.283 (4)	136
C10—H10A⋯O3ⁱ	0.93	2.49	3.330 (3)	150
C10—H10A⋯N2ⁱ	0.93	2.42	3.183 (3)	139

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Symmetry code: (i) Inline graphic .

Acknowledgments

HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship. AMI thanks the Department of Atomic Energy, Board for Research in Nuclear Sciences, Government of India, for the Young Scientist award.

supplementary crystallographic information

Comment

4,5,6,7-Tetrahydrothieno[3,2-c]pyridine derivatives are extensively studied in medicinal chemistry due to their various biological activities (Lopez-Rodriguez et al., 2001). 4,5,6,7-Tetrahydrothieno[3,2-c] pyridine oxadiazole derivatives are mainly used in CNS functions and disorders such as schizophrenia (Roth et al., 1994), depression, epilepsy, migraine, and control of circadian rhythm (Ying & Rusak, 1997).

The molecular structure of the title compound, Fig. 1, contains five rings, namely, A (N3/C1,C2,C5–C7), B (N1/N2/O1/C12,C13), C (S3/C2–C5), D (S1/C8–C11) and E (N4/C14–C18). The tetrahydropyridine (N3/C1,C2,C5–C7) ring adopts a half-chair conformation with puckering parameters Q = 0.497 (3) Å, θ = 131.5 (3)° and φ = 141.6 (4)° with the flap atom at C7 [maximum deviation of -0.338 (3) Å]. The dihedral angle between the least-squares planes of the rings are A/B = 54.76 (13)°, A/C = 5.66 (13)°, A/D = 68.63 (13)°, A/E = 69.34 (13)°, B/C = 56.97 (14)°, B/D = 13.90 (14)°, B/E = 15.62 (13)°, C/D = 70.85 (13)°, and C/E = 70.88 (13)°.

In the crystal structure, (Fig. 2), adjacent molecules are connected via bifurcated C—H···N and C—H···O (Table 1) hydrogen bonds forming one-dimensional chains along the b-axis.

Experimental

To a mixture of 3-(6,7-dihydrothieno[3,2-c]pyridine-5(4H)-ylsulfonyl) thiophene-2-carbohydrazide (0.5 g, 0.0014 mol) and 5-bromopyridine-3-carboxylic acid (0.29 g, 0.0014 mol), neutral alumina (0.5 g) and POCl₃, (1.1 g, 0.007 mol) were added. The resulting mixture was irradiated in a microwave oven for 5 min. Mass analysis of the crude reaction mixture confirmed completion of the reaction. The reaction mixture was concentrated and the residue was purified by column chromatography to get title compound which was recrystallised using acetone. Yield: 68%, m.p. 429–431 K.