4-Phenyl-1,2,4-triazaspiro[4.6]undec-1-ene-3-thione

In the title compound, C14H17N3S, the plane of the phenyl ring makes a dihedral angle of 74.90 (4)° with that of the triazathione ring (r.m.s. deviation = 0.001 Å), while the seven-membered ring adopts a twist-chair conformation. No specific intermolecular interactions are discerned in the crystal packing.

In the title compound, C 14 H 17 N 3 S, the plane of the phenyl ring makes a dihedral angle of 74.90 (4) with that of the triazathione ring (r.m.s. deviation = 0.001 Å ), while the seven-membered ring adopts a twist-chair conformation. No specific intermolecular interactions are discerned in the crystal packing.
Manchester Metropolitan University, Tulane University and Erciyes University are gratefully acknowledged for supporting this study.

Comment
Spiro-compounds are a significant class of of organic compounds due to their wide spectrum of pharmaceutical and applied chemistry aspects. They showed very promising biological activities such as anticancer agents (Chin et al., 2008) and antimicrobial agents (Thadhaney et al., 2010). Some spiro-compounds have also been recently used as antioxidants (Sarma et al., 2010). In this context and as part of our on-going study in synthesis of spiro-compounds for the purpose of biological potential, we report in this study the synthesis and crystal structure determination of the title compound.

Experimental
A mixture of 1 mmol (261 mg) of cycloheptan-1-one N-phenylthiosemicarbazone and 1 mmol (246 mg) of 2,3,5,6-tetrachloro-1,4-benzoquinone (DDQ) in 30 ml of ethyl acetate was stirred at room temperature. The reaction was monitored by TLC until completion. The precipitated DDQ-H 2 was filtered off and the filtrate was concentrated by slow evaporation in air to afford the corresponding product. The crude product was recrystallized from ethanol to furnish orange block crystals suitable for X-ray diffraction.

Refinement
H-atoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.99 Å). All were included as riding contributions with isotropic displacement parameters 1.2 times those of the attached atoms.  Title compound with 50% probability displacement ellipsoids for non-H atoms.

4-Phenyl-1,2,4-triazaspiro[4.6]undec-1-ene-3-thione
Crystal data C 14 H 17 N 3 S M r = 259.36 Triclinic, P1 Hall symbol: -P 1 a = 9.0578 (5) Å b = 9.1324 (5) Å c = 9.4637 (5) Å α = 88.2940 (8) where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.44 e Å −3 Δρ min = −0.20 e Å −3 Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S1