title: Crystal structure of febuxostat-acetic acid (1/1).
abstract: The asymmetric unit of the title compound [systematic name: 2-(3-cyano-4-iso-butyl-oxyphen-yl)-4-methyl-thia-zole-5-carb-oxy-lic acid-acetic acid (1/1)], C16H16N2O3S·CH3COOH, contains a febuxostat mol-ecule and an acetic acid mol-ecule. In the febuxostat mol-ecule, the thia-zole ring is nearly coplanar with the benzene ring [dihedral angle = 3.24 (2)°]. In the crystal, the febuxostat and acetic acid mol-ecules are linked by O-H⋯O, O-H⋯N hydrogen bonds and weak C-H⋯O hydrogen bonds, forming supra-molecular chains propagating along the b-axis direction. π-π stacking is observed between nearly parallel thia-zole and benzene rings of adjacent mol-ecules; the centroid-to-centroid distances are 3.8064 (17) and 3.9296 (17) Å.
authors.affiliation: Chemistry Department, Zhejiang University, Hangzhou, Zhejiang 310028, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.affiliation: Chemistry Department, Zhejiang University, Hangzhou, Zhejiang 310028, People's Republic of China.
authors.forename: Xiu-Rong
authors.initials: XR
authors.lastname: Hu
authors.affiliation: Chemistry Department, Zhejiang University, Hangzhou, Zhejiang 310028, People's Republic of China.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Gu
authors.affiliation: Chemistry Department, Zhejiang University, Hangzhou, Zhejiang 310028, People's Republic of China.
authors.forename: Gu-Ping
authors.initials: GP
authors.lastname: Tang
keywords: acetic acid; co-crystal; crystal structure; febuxostat; hydrogen bonding; π–π stacking