Cephalexin: a channel hydrate.
The antibiotic cephalexin [systematic name: D-7-(2-amino-2-phenylacetamido)-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid] forms a range of isomorphic solvates, with the maximum hydration state of two water molecules formed only at high relative humidities. The water content of the structure reported here (C(16)H(17)N(3)O(4)S.1.9H(2)O) falls just short of this configuration, having three independent cephalexin molecules, one of which is disordered, and 5.72 observed water molecules in the asymmetric unit. The facile nature of the cephalexin solvation/desolvation process is found to be facilitated by a complex channel structure, which allows free movement of solvent in the crystallographic a and b directions.
Kennedy
Alan R
AR
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, Scotland. a.r.kennedy@strath.ac.uk
Okoth
Maurice O
MO
Sheen
David B
DB
Sherwood
John N
JN
Teat
Simon J
SJ
Vrcelj
Ranko M
RM
D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002506:Cephalexin / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007473:Ion Channels / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D014867:Water / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D007473:Ion Channels; D014867:Water; D002506:Cephalexin