N-Phenyl-4-(8-phenyl-4,5-dihydro-1,2-benzoxazolo[4,5-d]thiazol-2-yl)piperidine-1-carboxamide

In the title molecule, C26H24N4O2S, the dihedral angle between the isoxazole ring and the adjoining benzene ring is 21.4 (5)°, and between the isoxazole ring and the thiazole ring is 14.3 (4)°. The piperidine ring is in a chair conformation. In the crystal structure, molecules are linked by intermolecular N—H⋯O and weak C—H⋯O hydrogen bonds into one-dimensional chains along [001].

In the title molecule, C 26 H 24 N 4 O 2 S, the dihedral angle between the isoxazole ring and the adjoining benzene ring is 21.4 (5) , and between the isoxazole ring and the thiazole ring is 14.3 (4) . The piperidine ring is in a chair conformation. In the crystal structure, molecules are linked by intermolecular N-HÁ Á ÁO and weak C-HÁ Á ÁO hydrogen bonds into onedimensional chains along [001].

Comment
We are interested in the title compound as a potential D1 protease inhibitor. D1 protease is a potential herbicidal target (Duff et al. 2007). To find the possible D1 inhibitors, virtual screening was performed and a molecule containing isoxazole, thiazole and piperidine rings was designed and synthesized (Hu et al. 2009).
The title moleclue ( Fig. 1) contains isoxazole, thiazole, piperdine and two benzene rings. The dihedral angle between the the isoxazole ring and the adjoining benzene ring is 21.4 (5)° and the dihedral angle between the isoxazole and the thiazole rings is 14.3 (4)°. The piperidine ring is in a chair conformation. In the crystal structure, molecules are linked by intermolecular N-H···O and weak C-H···O hydrogen bonds into one-dimensional chains along [001] (see Fig. 2).
Experimental 3-phenyl-6,7-dihydrobenzo[d]isoxazole-4(5H)-one was synthesized by a literature method (Bond et al., 2003). This intermediate (1 mmol) was treated with NBS (2.5 mmol) and NH 4 OAc (0.1 mmol) in dry ether to obtain the monobromo ketone and a trace amounts of polybromonated derivatives. The target product was formed by a published procedure (Hu et al., 2009). Slow diffusion of hexane into a ethyl acetate solution of the title compound gave single crystals suitable for X-ray analysis.

Refinement
All H atoms bonded to C atoms were placed in geometrically idealized positions and included in a riding-model approximation with C-H = 0.93 Å (aromatic), 0.97Å (methylene) and 0.98Å (methine), with U iso (H) = 1.2U eq (C). The H atom bonded to N4 was found in a difference Fourier map and refined with the restraint of N-H = 0.86 (2)Å and U iso (H) = 1.2U eq (N). Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 10% probability level. supplementary materials  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.