The Crystal and Molecular Structure of (±)-(‘E, ’)-N-Acetylpiperidine-2-carboxylic Acid

The crystal structure of N-acetylpiperidine-2-carboxylic acid has been determined by single-crystal X-ray diffraction methods at 295(1) K and refined by least squares to a residual of 0.039 for 846 ‘observed’ reflections. Crystals are orthorhombic, with space group P bca, a 13.684(6), b 11.602(4), c 11.171(4) Å, Z 8. The ring is a chair structure in which, contrary to an earlier proposal based on 1H n.m.r. studies, there is almost perfect staggering about the C(2)-C(3) bond.