3-Ethyl-6-(4-fluoro­phen­yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thia­diazine

S Jeyaseelan; H C Devarajegowda; R Sathishkumar; Agnes Sylvia D’souza; Alphonsus D’souza

doi:10.1107/S160053681202185X

. 2012 May 23;68(Pt 6):o1860. doi: 10.1107/S160053681202185X

3-Ethyl-6-(4-fluorophenyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine

S Jeyaseelan ^a, H C Devarajegowda ^a,^*, R Sathishkumar ^b, Agnes Sylvia D’souza ^c, Alphonsus D’souza ^c

PMCID: PMC3379427 PMID: 22719625

Abstract

In the title compound, C₁₂H₁₁FN₄S, the thiadiazine ring adopts a twist-boat conformation. The dihedral angle between the triazolothiadiazine system and the benzene ring is 10.54 (9)°. The crystal structure is characterized by C—H⋯N hydrogen bonds. The crystal packing also exhibits π–π interactions, with a centroid–centroid distance of 3.6348 (15) Å.

Related literature

For biological properties of triazolothiadiazines, see: Feng et al. (1992 ▶); Mohan & Anjaneyalu (1987 ▶); Holla et al. (2001 ▶); Walser et al. (1991 ▶); Hirota et al. (1991 ▶); Bradbury & Rivett (1991 ▶); Heindel & Reid (1980 ▶); Heidelberger et al. (1957 ▶). For related structures, see: Andersson & MacGowan (2003 ▶); Novak et al. (2006 ▶).

Experimental

Crystal data

C₁₂H₁₁FN₄S
M _r = 262.31
Monoclinic,
a = 13.322 (3) Å
b = 13.017 (3) Å
c = 7.1912 (16) Å
β = 105.308 (4)°
V = 1202.8 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.27 mm⁻¹
T = 293 K
0.24 × 0.20 × 0.12 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.770, T _max = 1.000
11097 measured reflections
2119 independent reflections
1828 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.106
S = 1.06
2119 reflections
164 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681202185X/bt5922sup1.cif

e-68-o1860-sup1.cif^{(17.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681202185X/bt5922Isup2.hkl

e-68-o1860-Isup2.hkl^{(102.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681202185X/bt5922Isup3.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
C1—H1⋯N2ⁱ	0.93	2.51	3.428 (3)	172
C8—H8A⋯N1ⁱⁱ	0.97	2.50	3.410 (3)	156
C8—H8B⋯N2ⁱ	0.97	2.30	3.228 (3)	160

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

Acknowledgments

The authors thank Professor T. N. Guru Row, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, for the data collection. SJ thanks the University Grants Commission (India), for the award of a Teacher Fellowship under the Faculty Development Programme (UGC-SWRO File No.: FIP/11 th Plan/KAMY006 TF, Dt.: 06/08/2010).

supplementary crystallographic information

Comment

Triazoles fused with six membered ring systems are found to be associated with diverse pharmacological activity. A number of thiadiazines have been shown to exhibit antimicrobial (Feng et al., 1992) and dieretic properties (Mohan et al., 1987) and also serves as photographic couplers (Holla et al., 2001). The analgesic, anti-asthmatic, diuretic, anti-hypertensive, anti-cholinergic, antibacterial, antifungal, anti-inflammatory, hypoglycemic, anti-tubercular and antiviral properties exhibited by various N-bridged heterocycles derived from a variety of 4-amino-5-mercapto-1,2,4-triazoles, have made them an important chemotherapeutic agents (Walser et al., 1991; Hirota et al., 1991; Bradbury et al., 1991). The 1,2,4- triazoles nucleus has recently been incorporated into a wide variety of therapeutically interesting drugs including H1/H2 histamine receptor blockers, cholinesterase active agents, CNS stimulants, anti-anxiety agents and sedatives (Heindel et al., 1980). Further fluorinated heterocycles have been shown to possess wide variety of biocidal activities. Compounds such as fluorouracil and fluoroquinolone have been used as anticancer agents and antibiotics (Heidelberger et al., 1957; Andersson et al., 2003; Novak et al., 2006).

The asymmetric unit of 3-ethyl-6-(4-fluorophenyl)-7H-[1,2,4]triazolo[3,4-b] [1,3,4]thiadiazine is shown in Fig. 1. The triazolo-thiadiazine ring system is not planar. The dihedral angle between the triazolo-thiadiazine ring system (S1/N1–N4/C7–C10) and the benzene ring (C1–C6) is 10.54 (9)°.

In the crystal structure (Fig. 2), the molecules are connected via intermolecular C1—H1···N2, C8—H8A···N1 and C8—H8B···N2 hydrogen bonds (Table 1). Furthermore, the crystal structure features a π-π interaction, with a centroid-centroid Cg1 (C9/C10/N1–N3) distance of 3.5728 (16) Å.

Experimental

A mixture of triazole (1) (0.01 mol) and p-fluorophenacyl bromide (0.01 mol) in ethanol (25 ml) was heated under reflux for 1–2 hrs. The reaction mixture was cooled to room temparature and neutralized with sodium acetate (5%). The precipitated triazolothiadiazines were collected by filtration, washed with water and recrystallized from ethanol. Yield 82%; m.p.455 K.