I. INTRODUCTION
The title compound azilsartan (Figure 1), systematic name 2-Ethoxy-1-[[2′-(4,5-dihydro-5-oxo-12,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid, is a new angiotensin II (AII) receptor blocker (ARB) that inhibits the binding of AII to AII type 1 (AT1) receptors selectively, and is thus expected to exert a more potent and sustained blood pressure lowering effect than existing ARBs (Hiromi et al., Reference Hiromi, Kazuaki, Kenkichi and Yoshinori2012).
Figure 1. Structural formula of azilsartan.
The single crystallographic data of azilsartan [a = 9.6590 (19) Å, b = 11.329 (2) Å, c = 20.046 (4) Å, α = 90°, β = 90.30 (3)°, γ = 90°, unit-cell volume V = 2193.54 Å3, Z = 4, and space group P21/c] was obtained by Ge et al. (Reference Ge, Li and Cheng2016). The Powder X-ray diffraction (PXRD) data have recorded in Powder Diffraction File (PDF)-4/Organic 2016 database with the PDF numbers 00-063-1112. In this study, we provided a calculated PXRD pattern and Fourier transform infrared spectroscopy (FTIR) spectrum for azilsartan. The experimental data can collaborate with the earlier data.
II. EXPERIMENTAL
A. Sample preparation
The sample (Figure 1) was purchased from Tianjin Heowns Biochem LLC (China). The melting point and measured density of the title compound are 200–201°C and 1.383 g cm−3, respectively. The FTIR spectrum of the title compound was presented in Figure SI. Crystallization of azilsartan at room temperature was successful using methanol as solvent. Then, part of crystals were dried and ground into powder.
B. Diffraction data collection and reduction
The PXRD measurement was performed at room temperature using an X'Pert PRO diffractometer (PANalytical Co., Ltd., The Netherlands) with a PIXcel 1D detector and CuKα radiation (generator setting: 40 kV and 40 mA). The diffraction data were collected over the angular range from 4 to 50° 2θ with a step size of 0.01313° 2θ and a counting time of 30 ms step−1 (Figure 2).
Figure 2. (Colour online) XRD pattern of azilsartan using CuKα radiation (black line) and the simulated pattern of ours (red line).
The software package Material Studio 8.0 (Accelrys Co., Ltd., CA, USA) was used to process the data in the Analytical & Testing Center (Sichuan University, Chengdu, China). The PXRD pattern was pre-treated by subtracting the background, smoothing, and stripping off the Kα 2 component. Automatic indexing results were obtained by the X-Cell method (Neumann, Reference Neumann2003). The indexing results were then refined using Pawley (Pawley, Reference Pawley1981), which involves assigning the Miller indices (h, k, l) to each observed peak in the experimental PXRD pattern.
C. Single-crystal XRD
XRD data for azilsartan were collected on an Xcalibur, Eos diffractometer. The crystal was kept at 293.15 K during data collection. The structure was solved with olex2 (Dolomanov et al., Reference Dolomanov, Bourhis, Gildea, Howard and Puschmann2009), a structure solution program using charge flipping and refined with the ShelXL (Sheldrick, Reference Sheldrick2008). Structure solution program using Direct Methods and refined with the ShelXL (Sheldrick, Reference Sheldrick2015) refinement package using least-squares minimization.
III. RESULTS
Pawley refinement results confirmed that the title compound is monoclinic with space group P21/c and unit-cell parameters: a = 9.641(3) Å, b = 11.301(9) Å, c = 20.010(8) Å, α = 90°, β = 90.351(5)°, γ = 90°, unit-cell volume V = 2196.735(4) Å3, Z = 4, and ρ cal = 1.379 g cm−3. The values of 2θ obs, d obs, I obs, h, k, l, 2θ cal, d cal, and Δ2θ are listed in Table I. The results were in good agreement with the single crystallographic data of ours [a = 9.6649(3) Å, b = 11.3218(3) Å, c = 20.0104(7) Å, α = 90°, β = 90.285(3)°, γ = 90°, unit-cell volume V = 2189.60(12) Å3, Z = 4, ρ cal = 1.385 g cm−3]. The detail single crystallographic data of azilsartan and the experimental data were listed in Table SI. The comparison of the experimental PXRD pattern with the simulated pattern of ours is shown in Figure 2. Results showed that both single-crystal and powder diffraction methods can get similar structure data.
Table I. Indexed X-ray powder diffraction data for azilsartan
The d-values were calculated using CuKα 1 radiation (λ = 1.54056 Å).
SUPPLEMENTARY MATERIAL
The supplementary material for this article can be found at https://doi.org/10.1017/S0885715618000210.
