8-(2-Chloro­phen­yl)-1-(4-chloro­phen­yl)-4-[(E)-(2-chloro­phen­yl)methyl­idene]-6-methyl-4,5,6,7,7a,8-hexa­hydro-1,2,4-oxadiazolo[5,4-d]pyrido[3,4-c][1,5]benzothia­zepine

V Rajni Swamy; R Sudha Periathai; K Rajagopal; R V Krishnakumar; N Srinivasan

doi:10.1107/S1600536810013309

. 2010 Apr 21;66(Pt 5):o1119. doi: 10.1107/S1600536810013309

8-(2-Chlorophenyl)-1-(4-chlorophenyl)-4-[(E)-(2-chlorophenyl)methylidene]-6-methyl-4,5,6,7,7a,8-hexahydro-1,2,4-oxadiazolo[5,4-d]pyrido[3,4-c][1,5]benzothiazepine

V Rajni Swamy ^a, R Sudha Periathai ^b, K Rajagopal ^c, R V Krishnakumar ^a, N Srinivasan ^a,^*

PMCID: PMC2979104 PMID: 21579170

Abstract

In the title compound, C₃₃H₂₆Cl₃N₃OS, the oxadiazole, piperidine and benzothiapezine rings adopt envelope, chair and twist-boat conformations, respectively. In the crystal, the molecular aggregation is characterized by chains of centrosymmetrically related pairs connected through Cl⋯Cl interactions [3.533 (2) Å], extending parallel to (202).

Related literature

For the biological importance of benziothiazepines and oxadiazol derivatives, see: Budriesi et al. (2007 ▶); Sahin et al. (2002 ▶). For ring geometry, see: Boeyens (1978 ▶); Cremer & Pople (1975 ▶). For a related structure, see: Srinivasan et al. (2007 ▶).

Experimental

Crystal data

C₃₃H₂₆Cl₃N₃OS
M _r = 618.98
Triclinic,
a = 11.015 (3) Å
b = 11.758 (4) Å
c = 11.988 (4) Å
α = 78.87 (2)°
β = 86.89 (3)°
γ = 78.29 (2)°
V = 1491.5 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.41 mm⁻¹
T = 298 K
0.30 × 0.15 × 0.15 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.90, T _max = 0.94
42055 measured reflections
11096 independent reflections
7867 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.146
S = 1.03
11096 reflections
372 parameters
H-atom parameters constrained
Δρ_max = 0.64 e Å⁻³
Δρ_min = −0.62 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810013309/nc2178sup1.cif

e-66-o1119-sup1.cif^{(27.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810013309/nc2178Isup2.hkl

e-66-o1119-Isup2.hkl^{(531.6KB, hkl)}

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

Acknowledgments

The authors thank the Sophisticated Analytical Instrumentation Facility (SAIF), Indian Institute of Technology, Chennai, for the X-ray intensity data collection.

supplementary crystallographic information

Comment

The title compound, C₃₃H₂₆N₃OCl₃ S, belongs to an important class of heterocycles which exhibit antihypertensive properties. The compound consists of a benzothiazepine, a oxadiazole and a methyl piperidine ring. Benziothiazepines are regarded as a class of calcium channel blockers (Budriesi et al., 2007), oxadiazol derivatives are established as micobicides (Sahin et al., 2002) and piperidines are established as key components of anti-Parkinson's drugs. Accurate description of the molecular geometry of such molecules are indispensable to proceed with the pharmacological investigations which may prove useful in the design of drugs with a wide range of activities. Also, the role of non-conventional hydrogen bonds viz. C—H···X (X= N, O, Cl, F, etc.) in influencing the geometry of the molecular packing can be unambiguously assessed. Recently, an anlogue of the title compound namely, the crystal structure of 1-(4-chlorophenyl)- 8-(4-fluorophenyl)-4-[(E)-(4-fluorophenyl)methylidene]-6-methyl-4,5,6,7,7a, 8-hexahydro[1,2,4]oxadiazolo[5,4-d]pyrido [3,4-c][1,5] benzothiazepine (Srinivasan et al., 2007) was elucidated.

A least-squares plane calculations show that the 2-chlorophenyl attached to thiazepine, 2-chlorophenyl attached to piperidine and 4-chlorophenyl ring of the oxadiazole ring make a dihedral angle of 34.8 (1) °, 51.3 (1) ° and 73.9 (1) °, respectively, with respect to the benzene fused to the thiazepine ring. The torsion angles about the methylidene bond C4—C40—C41—C42 = 39.8 (2) ° and C4—C40—C41—C46 = -141.8 (2) ° indicates a significant twist of the 2-chlorophenyl ring which may be attributed to steric factors. These values that describe the molecular geometry slightly differ from those observed in the 4-fluoro-4-fluoro- 4-chloro analogue (Srinivasan et al., 2007). The oxadiazole, piperidine and benzothiapezine rings adopt the usually expected envelope, chair and twist-boat conformations, respectively. The molecular aggreagation is characterized by linear chains of centrosymmetrically related pairs extending parallel to the (202) plane and connected through Cl···Cl interactions [Cl1···Cl2(-x+1,-y,-z+2) = 3.533 (2) Å. Other Cl···Cl distances observed are Cl2···Cl2(-x+1,-y+1,-z+1) = 3.826 (2) Å and Cl1···Cl3(x,+y-1,+z+1) = 3.952 (2) Å.

Experimental

2-Methyl-11-(2-chlorophenyl)-4-[(E)-(2-chlorophenyl)methylidene]- 1,2,3,4,11,11a-hexahydro-pyrido[3,4-c][1,5]benzothiazepines (1 mmol) and 4-chloro-N-hydroxybenzenecarboximidoyl chloride (1 mmol) were dissolved in benzene (15 ml). Triethylamine (1 mmol) was added to the mixture and refluxed for 20 to 30 min. After completion of the reaction as evident from thin layer chromatography the triethylamine hydrochloride was filtered off, solvent evaporated, product was purified by column chromatography using petroleum ether:ethyl acetate (90:10 v/v) mixture and finally recrystallized from ethyl acetate to obtain pure 1-(4-chlorophenyl)-8-(2-chlorophenyl) -4-[(E)-(2-chlorophenyl)methylidene]-6-methyl-4,5,6,7,7a,8- hexahydro[1,2,4]oxa-diazolo[5,4-d]pyrido[3,4-c][1,5] benzothiazepine as colorless crystals.