N-(4-Hydroxyphenyl)-2-(1,1,3-trioxo-2,3-dihydro-1,2-benzothiazol-2-yl)acetamide

In the title compound, C15H12N2O5S, the benzisothiazole group is approximately planar (r.m.s. deviation excluding H atoms and the two O atoms bonded to S = 0.023 Å). The dihedral angle between the benzisothiazole ring and the terminal phenol ring is 84.9 (1)°. In the crystal, molecules are joined by N—H⋯O and O—H⋯O hydrogen bonds, and π-stacking interactions are observed between alternating phenol and benzisothiazole rings [centroid–centroid distances = 3.929 (3) and 3.943 (3) Å].

In the title compound, C 15 H 12 N 2 O 5 S, the benzisothiazole group is approximately planar (r.m.s. deviation excluding H atoms and the two O atoms bonded to S = 0.023 Å ). The dihedral angle between the benzisothiazole ring and the terminal phenol ring is 84.9 (1) . In the crystal, molecules are joined by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds, andstacking interactions are observed between alternating phenol and benzisothiazole rings [centroid-centroid distances = 3.929 (3) and 3.943 (3) Å ].
Helpful discussions with Professor M. L. Trudell, University of New Orleans, are gratefully acknowledged.

Comment
Analgesics currently in use have high incidence of adverse reactions and can cause potentially lethal effects like hepatotoxicity and nephrotoxicity (Slattery et al., 1996;McGoldrick & Bailie, 1997;Watkins et al., 2006). A series of compounds bearing the acetaminophen (Tylenol) fragment linked to different lipophilic heterocyclic moieties were synthesized with a view to modulate its pharmacokinetic profile (Bazan & Alvarez-Builla, 1996a,b6;Vaccarino et al., 2007). Of these new derivatives, the title compound (commonly called SCP-1) has a similar profile to that of acetaminophen but with shorter elimination half-life and clearance.

Experimental
The title compound was synthesized following the procedure described by Vaccarino et al. (2007) and colourless needles suitable for X-ray analysis were obtained by recrystallization from an ethanol-water (8:1) mixture.

Refinement
All H atoms were located in a difference density map and their positional parameters and U iso included in the full-matrix least-squares refinement. Observed C-H bond lengths are in the range 0.91 (3)-0.97 (3) Å. Fig. 1. The asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 50% probability level.  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.