(3aR*,7aS*)-1-(p-Tolylsulfonyl)perhydroindol-2-one

In the racemic title compound, C15H19NO3S, the dihedral angle between the planes of the benzene ring and the O=S=O group is 56.92 (7)° and the cyclohexane ring adopts a chair conformation.

In the racemic title compound, C 15 H 19 NO 3 S, the dihedral angle between the planes of the benzene ring and the O S O group is 56.92 (7) and the cyclohexane ring adopts a chair conformation.

Related literature
For related structures, see: Brion et al. (1992) (3aR*,7aS*)-1-(p-Tolylsulfonyl)perhydroindol-2-one L. Fang, X.-B. Fang and L. Chen Comment Trandolapril, a potent angiotensin-converting enzyme (ACE) inhibitor, has been widely used for the treatment of hypertension (De Ponti et al., 1991). However, its synthesis procedure is relatively complicated, especially to construct the stereochemical centers of the molecule. To solve the problem, many methods have been proposed in the past years (Brion et al., 1992). Introducing chiral auxiliary-induced stereoselective groups is one of the most promising synthetic strategies since it requires fewer reactions steps and lead to high enantioselectivity. Currently, using p-toluenesulfonyl group as stereoselectivity-inducing group, we have successfully synthesized the title compound as a key intermediate for the synthesis of trandolapril.
In the compound, the S=O distances are 1.4261 (19) and 1.426 (2) Å, and the angle of O=S=O is 119.20 (12)deg. The angle of the benzene ring and the plane of O=S=O is 56.92 (7) deg. Meanwhile, the cyclohexane portion adpots a chair structure.

Refinement
All the H atoms were positioned geometrically and refined using a riding model with C-H = 0.95-1.00 Å, and with U iso (H) = 1.5 for the H atoms of methyl group and 1.2 U iso (C) for other H atoms.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds supplementary materials sup-3 in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness 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 threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) 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.