4-(Piperidin-1-yl)-4H-benzo[b]tetrazolo[1,5-d][1,4]diazepin-5(6H)-one

There are two crystallographically unique molecules present in the asymmetric unit of the title compound, C14H16N6O; in both molecules, the seven-membered diazepinone ring adopts a boat-like conformation and the chair conformation piperidine ring is an axial substituent on the diazepinone ring. In the crystal, each molecule forms hydrogen bonds with its respective symmetry equivalents. Hydrogen bonding between molecule A and symmetry equivalents forms two ring motifs, the first formed by inversion-related N—H⋯O interactions and the second formed by C—H⋯O and C—H⋯N interactions. The combination of both ring motifs results in the formation of an infinite double tape, which propagates in the a-axis direction. Hydrogen bonding between molecule B and symmetry equivalents forms one ring motif by inversion-related N—H⋯O interactions and a second ring motif by C—H⋯O interactions, which propagate as a single tape parallel with the c axis.

There are two crystallographically unique molecules present in the asymmetric unit of the title compound, C 14 H 16 N 6 O; in both molecules, the seven-membered diazepinone ring adopts a boat-like conformation and the chair conformation piperidine ring is an axial substituent on the diazepinone ring. In the crystal, each molecule forms hydrogen bonds with its respective symmetry equivalents. Hydrogen bonding between molecule A and symmetry equivalents forms two ring motifs, the first formed by inversion-related n-hÁ Á Áo interactions and the second formed by c-hÁ Á Áo and c-hÁ Á Án interactions. the combination of both ring motifs results in the formation of an infinite double tape, which propagates in the a-axis direction. hydrogen bonding between molecule B and symmetry equivalents forms one ring motif by inversion-related n-hÁ Á Áo interactions and a second ring motif by c-hÁ Á Áo interactions, which propagate as a single tape parallel with the c axis.

Related literature
The structure of the title compound was determined as part of a larger study on development of synthetic methods for highthroughput medicinal chemistry. For background to the use of multi-component reactions in high-throughput medicinal chemistry, see: Gunawan et al. (2010);hulme & dietrich (2009);hulme & gore (2003). for the ugi reaction, see: ugi & steinbrü ckner (1961). for graph-set notation for hydrogen bonding, see: bernstein et al. (1995) and puckering parameters, see : cremer & pople (1975 Table 1 Hydrogen-bond geometry (Å , ). The asymmetric unit of 4 is shown in Figure 2. There are two crystallographically unique molecules in the asymmetric unit; the molecule composed of atoms O1 to C14 will henceforth be referred to as "molecule A" and the molecule composed of atoms O51 to C64 referred to as "molecule B". Where appropriate, discussion will be limited to molecule A with results for molecule B presented in square brackets. Molecular dimensions are unexceptional.
In the crystal each molecule forms hydrogen bonds with its respective symmetry equivalents. Hydrogen bonding between molecule A and symmetry equivalents forms two ring motifs (Bernstein et al., 1995), an R 2 2 (8) motif formed by inversionrelated N-H···O interactions and an R 2 2 (9) motif formed by C-H···O and C-H···N interactions. The combination of both ring motifs results in the formation of an infinite double tape which propagates in the a axis direction (Figure 4). Hydrogen bonding between molecule B and symmetry equivalents forms one ring motif composed of an R 2 2 (8) motif formed by inversion-related N-H···O interactions and an R 2 2 (10) motif formed by C-H···O interactions ( Figure 5). This propagates as a single tape parallel with the c axis.

Experimental
A solution of piperidine (0.017 g, 0.20 mmol) and ethyl glyoxylate (0.04 ml, 50% in toluene, 0.20 mmol) in methanol (0.5 ml) were stirred at room temperature. After 5 minutes, ortho-N-Boc-phenylisonitrile (0.0436 g, 0.20 mmol) and trimethylsilylazide (0.023 g, 0.20 mmol) was added dropwise to the above solution and stirred at room temperature for 23 h. The solvent was evaporated in vacuo and the product was purified using column chromatography (5-30% Hexane/Ethyl Acetate) to afford the desired Ugi product (0.056 g, 0.20 mmol, 65%) as colorless oil. The purified Ugi product was treated with 10% trifluoroacetic acid in dichloroethane (4 ml) and irradiated in a Biotage Initiator&trade; for 10 minutes at 120°C.

Refinement
All hydrogen atoms were located in a difference Fourier map and are freely refined.       (14)