3-tert-Butyl-1H-isochromene-1-thione

The title compound, C13H14OS, crystallizes with two independent molecules in the asymmetric unit. The unit cell contains three voids of 197 Å3, but the residual electron density (highest peak = 0.24 e Å−3 and deepest hole = −0.18 e Å−3) in the difference Fourier map suggests no solvent molecule occupies this void. The crystal structure is stabilized by π–π interactions between the isocoumarin ring systems, with centroid–centroid distances of 3.6793 (14) and 3.6566 (15) Å.

The title compound, C 13 H 14 OS, crystallizes with two independent molecules in the asymmetric unit. The unit cell contains three voids of 197 Å 3 , but the residual electron density (highest peak = 0.24 e Å À3 and deepest hole = À0.18 e Å À3 ) in the difference Fourier map suggests no solvent molecule occupies this void. The crystal structure is stabilized byinteractions between the isocoumarin ring systems, with centroid-centroid distances of 3.6793 (14) and 3.6566 (15) Å .
The isocoumarin moieties in the symmetric unit of the title compound, (I), ( Fig. 1a and Fig. 1 b), are essentially parallel to each other with a small dihedral angle of 1.20 (7) °.

Experimental
The 3-tert-butyl-1H-isochromen-1-one and Lawessons reagent were taken in toluene (1:1 ratio) and refluxed for 1 h. Then the reaction mass was quenched with water, extracted with dichloromethane, washed with water, dried, concentrated and purified by column chromatography to get the titled compound. Single crystals of the title compound were obtained via recrystalization from a chloroform solution.

Refinement
All H-atoms were placed in calculated positions (C-H = 0.93 and 0.96 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 or 1.5U eq (C). In the crystal structure, there is an 197 Å 3 void, but the low electron density (0.24 e.Å -3 ) in the difference Fourier map suggests no solvent molecule occupying this void.  Fig. 1. The first molecule in the asymmetric unit with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.  3-tert-Butyl-1H-isochromene-1-thione

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 esds 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.