title: Protonation site and hydrogen bonding in anhydrous and hydrated crystalline forms of doxazosin mesylate from powder data.
abstract: The three-dimensional solid-state structures of two modifications of doxazosin mesylate (C23H26N5O5)+.(CH3SO3)-, 4-amino-2-[4-[(2,3-dihydro-1,4-benzodioxin-2-yl)carbonyl]piperazin-1-yl]-6,7-dimethoxyquinazoline methanesulfonate, a commonly used antihypertensive agent, have been determined by synchrotron X-ray powder diffraction. An anhydrous form (A) and a dihydrate form (dG) crystallize in monoclinic space groups. In both forms the doxazosin molecule is protonated at the N1 atom of the quinazoline bicycle. The N1 atom, and the amino H atoms and O atoms of the mesylate moieties are involved in three-dimensional hydrogen-bonding networks, while solvent water molecules and carboxamide O atoms are also incorporated in a hydrogen-bonding network in dG.
authors.affiliation: Department of Chemistry, Moscow State University, 119992 Moscow, Russia. vladimir@struct.chem.msu.ru
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Chernyshev
authors.forename: Denis
authors.initials: D
authors.lastname: Machon
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Fitch
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Zaitsev
authors.forename: Alexandr V
authors.initials: AV
authors.lastname: Yatsenko
authors.forename: Alexandr N
authors.initials: AN
authors.lastname: Shmakov
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Weber
mesh_terms: D003460:Crystallization; D017292:Doxazosin / Q000737:chemistry*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D014867:Water / Q000737:chemistry
chemical_list: D011522:Protons; D014867:Water; D017292:Doxazosin