Nisbet Matthew L, Puzan Marissa, Wojtas Lukasz, Samas Brian, Wood Geoffrey P F
Pharmaceutical Sciences, Pfizer Global Research & Development, Groton, Connecticut 06340, USA.
Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
Acta Crystallogr E Crystallogr Commun. 2022 Mar 10;78(Pt 4):381-384. doi: 10.1107/S2056989022002110. eCollection 2022 Apr 1.
Ceftibuten, CHNOS, with the systematic name (6,7)-7-{[()-2-(2-amino-1,3-thia-zol-4-yl)-4-carb-oxy-but-2-eno-yl]amino}-8-oxo-5-thia-1-aza-bicyclo-[4.2.0]oct-2-ene-2-carb-oxy-lic acid, is a third generation, orally administered cephalosporin anti-biotic with broad anti-microbial activity and stability against extended spectrum β-lactamases. Ceftibuten can exist in various hydration states and to better understand the location of the water mol-ecules of crystallization and their effect on the structure, the crystal structures of anhydrous (I) and hydrated (II) ceftibuten were determined and both occur as zwitterions with proton transfer from the carboxyl-ate group adjacent to the β-lactam ring to the N atom of the thia-zole ring. The β-lactam ring in (I) is almost planar but the equivalent grouping in (II) is slightly buckled. In the extended structure of (I), O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network. In (II), O-H⋯O, N-H⋯O, O-H⋯O, N-H⋯O and O-H⋯O (c = ceftibuten, w = water) hydrogen bonds link the components into a three-dimensional network. A large void space is present within the anhydrous crystal structure that can accommodate between two and three mol-ecules of water.
头孢布烯，化学组成为CHNOS，系统命名为(6,7)-7-{[()-2-(2-氨基-1,3-噻唑-4-基)-4-羧基-2-丁烯酰基]氨基}-8-氧代-5-硫杂-1-氮杂双环-[4.2.0]辛-2-烯-2-羧酸，是一种第三代口服头孢菌素抗生素，具有广泛的抗菌活性且对超广谱β-内酰胺酶稳定。头孢布烯能以多种水合状态存在，为了更好地理解结晶水分子的位置及其对结构的影响，测定了无水（I）和水合（II）头孢布烯的晶体结构，二者均以两性离子形式存在，质子从β-内酰胺环相邻的羧酸根基团转移至噻唑环的N原子上。（I）中的β-内酰胺环几乎呈平面状，但（II）中的等效基团略有弯曲。在（I）的扩展结构中，O-H⋯O和N-H⋯O氢键将分子连接成三维网络。在（II）中，O-H⋯O、N-H⋯O、O-H⋯O、N-H⋯O和O-H⋯O（c = 头孢布烯，w = 水）氢键将各组分连接成三维网络。无水晶体结构内存在一个大的空隙空间，可容纳两到三个水分子。
