Crystal structure of cis-2-(2-carb-oxy-cyclo-prop-yl)glycine (CCG-III) monohydrate.
The title compound, C6H9NO4·H2O [systematic name: (αR,1R,2S)-rel-α-amino-2-carb-oxy-cyclo-propane-acetic acid monohydrate], crystallizes with two organic mol-ecules and two water mol-ecules in the asymmetric unit. The space group is P21 and the organic mol-ecules are enanti-omers, thus this is an example of a 'false conglomerate' with two mol-ecules of opposite handedness in the asymmetric unit (r.m.s. overlay fit = 0.056 Å for one mol-ecule and its inverted partner). Each mol-ecule exists as a zwitterion, with proton transfer from the amino acid carb-oxy-lic acid group to the amine group. In the crystal, the components are linked by N-H⋯O and O-H⋯O hydrogen bonds, generating (100) sheets. Conformationally restricted glutamate analogs are of inter-est due to their selective activation of different glutamate receptors, and the naturally occurring (+)-CCG-III is an inhibitor of glutamate uptake and the key geometrical parameters are discussed.
Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, USA.
Sergey
S
Lindeman
Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, USA.
Nathaniel J
NJ
Wallock
Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, USA.
William A
WA
Donaldson
conformationally restricted glutamate analog; crystal structure; cyclo­propane