GABA Agonists. X-Ray Crystallographic and 1H NMR Spectroscopic Investigations of (3RS,4RS)-3-Hydroxypiperidine-4-carboxylic Acid.

Abstract
The conformations of (3RS,4RS)-3-hydroxypiperidine-4-carboxylic acid (1) in the crystalline state and in aqueous solution were determined by X-ray crystallography and by 1PMR spectroscopy at 270 MHz, respectively. Crystal 1 exists in the chair conformation with the carboxylate group in an equatorial position and the hydroxy group in an axial position. Based on an analysis of the coupling constants in the 1PMR spectrum of 1, the compound seems to adopt predominantly a similar conformation in aqueous solution.