2-(Methylsulfanyl)cyclododecanone tosylhydrazone

The title compound, C20H32N2O2S2, has been synthesized by the reaction of α-methylsulfanylcyclododecanone and p-toluenesulfonylhydrazine. In the crystal structure, the conformation of the non-benzenoid ring is [3333] and the methylsulfanyl group is in the α-side exo position. The molecules are linked by intermolecular N—H⋯S hydrogen bonds.

The title compound, C 20 H 32 N 2 O 2 S 2 , has been synthesized by the reaction of -methylsulfanylcyclododecanone and ptoluenesulfonylhydrazine. In the crystal structure, the conformation of the non-benzenoid ring is [3333] and the methylsulfanyl group is in the -side exo position. The molecules are linked by intermolecular N-HÁ Á ÁS hydrogen bonds.
We acknowledge financial support of this investigation by the National Basic Research Program of China (2003CB114407).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2190).

Comment
Many derivatives of cyclododecanone have bioactivity that has attracted much attention from chemists (Song et al., 2005;Li et al., 2005). In order to understand the structure-activity relationships of these materials, it is necessary to study their stereochemistry and overall conformation. We have studied a number of α-monosubstituted cyclododecanones with some fruitful results (Wang et al.,2002;Lu et al.., 2004). Recently, we found a very interesting conformational phenomenon in the condensation products resulting from on the reactions of α-monosubstituted cyclododecanones with hydroxylamine and thiosemicarbazide (Wang et al., 2007). In these compounds the parent ring has a [3333] conformation and the substituting group is at the α-side-exo or α-corner-antiposition. These results were rationalized by "corner-position carbonyl participation" of raw materials, memory effects and H-bonding between amine derivatives and α-monosubstituted cyclododecanones.
To further understand the above results, we synthesized the title compound (I) by the reaction of α-methylsulfanylcyclododecanone and p-toluenesulfonylhydrazine. The X-ray analysis further confirmed the validity of our proposed explanation.
The molecular structure of the title compound is given in Fig.1. In the crystal, the parent ring has the [3333] conformation found in the other molecules and the methylsulfanyl group is at α-side-exo position. The molecules are linked by intermolecular N-H···S hydrogen bonds (Table 1 and Fig.2).
Experimental α-Methylsulfanylcyclododecanone(228 mg, 1.0 mmol) was dissolved in 10 ml absolute ethanol along with p-toluenesulfonylhydrazine (279 mg, 1.5 mmol) and a catalytic amount of p-toluenesulfonic acid. The reaction mixture was heated to reflux under nitrogen for 5 h and cooled. After removal of the solvent under reduced pressure, the crude product was purified by column chromatography on silica gel (200-300 mesh) using hexane/ethyl acetate (10:1,v/v) as the eluent, and recrystallized from methanol to give a pure colorless crystal (yield 76%, m.p. 136-138 °C) suitable for X-ray diffraction.

Refinement
All non-hydrogen atoms were refined with anisotropic displacement parameters. The carbon-bound H atoms were placed at calculated positions, with C-H = 0.93-0.98 Å, and included in the final cycles of refinement using a riding model with U iso (H) = 1.2 or 1.5(methyl) U eq (parent atom). The H atoms attached to N2 was located in a difference Fourier map, and was refined with a distance of N-H 0.85 (1) Å.  as large as those based on F, and R-factors based on ALL data will be even larger.