8-Methyl-4-morpholinoethyl-1-thia-4-azaspiro[4.5]decan-3-one

In the title compound, C15H26N2O2S, the cyclohexane and morpholine rings adopt chair conformations, while the thiazole ring has a twist conformation. An intramolecular C—H⋯S hydrogen-bond interaction forms a five-membered ring. The crystal packing involves C—H⋯O=C intermolecular interactions where carbonyl O atoms act as double acceptors to two symmetrically related H atoms.


Comment
Applications of multi-component reactions (MCRs) in all areas of applied chemistry are very popular because they offer a wealth of products, while requiring only a minimum of effort. The derivatives incorporating the thiazolidine ring system are interesting compounds due to their biological properties. Some 4-thiazolidinones interfere with essential bacterial enzymes (Andres et al., 2000) and they also exhibit antibacterial (Vicini et al., 2006), antimycobacterial (Küçükgüzel et al., 2002, anti-HIV-1 ( Barreca et al., 2001), and anticancer activities (Rao et al., 2004). A very recent article deals with similar structures demostrating potent antiproliferative activity for prostate cancer (Gududuru et al., 2004). As a part of an ongoing investigation on bioactive 4-thiazolidinones and related structures, we report here the synthesis and the crystal structure of title compound (I).

Experimental
A mixture of morpholinoethylamin (5 mmol), 4-methyl cyclohexanone (5 mmol) and thioglycolicacid (20 mmol) in dry benzene (20 ml) was refluxed for 6 h using a Dean-Stark water separator. Excess solvent was evaporated in vacuo. The residue was taken up in chloroform. The chloroform layer was triturated with saturated NaHCO 3 solution (2x) before drying over sodium sulfate and concentrated under reduced pressure to dryness. The crude product was purified by column chromatography on silica gel using hexane: acetone (80:20) as eluent to yield colourless prisms. IR (ν, cm -1 ): 1672 (C=O All H-atoms were placed in calculated positions [C-H = 0.96-0.97 Å] and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 or 1.5 U eq (C).
The highest residual electron density [0.71 e.A -3 ] was located at 0.86 Å from atom H1A and the deepest residual electron-density [-0.18 e.A -3 ] was located at 0.72 Å from atom S1. Probably due to the poor crystal quality, most of the reflections were weak. Analysis of the solvent void using PLATON (Spek, 2003) gave that unit cell contains no residual solvent accessible area.

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 tor-

sion angles
Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted Rfactors 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.