tert-Butyl (6S)-4-hydroxy-6-isobutyl-2-oxo-1,2,5,6-tetrahydropyridine-1-carboxylate and tert-butyl (4R,6S)-4-hydroxy-6-isobutyl-2-oxopiperidine-1-carboxylate.
X-ray studies reveal that tert-butyl (6S)-6-isobutyl-2,4-dioxopiperidine-1-carboxylate occurs in the 4-enol form, viz. tert-butyl (6S)-4-hydroxy-6-isobutyl-2-oxo-1,2,5,6-tetrahydropyridine-1-carboxylate, C14H23NO4, when crystals are grown from a mixture of dichloromethane and pentane, and has an axial orientation of the isobutyl side chain at the 6-position of the piperidine ring. Reduction of the keto functionality leads predominantly to the corresponding beta-hydroxylated delta-lactam, tert-butyl (4R,6S)-4-hydroxy-6-isobutyl-2-oxopiperidine-1-carboxylate, C14H25NO4, with a cis configuration of the 4-hydroxy and 6-isobutyl groups. The two compounds show similar molecular packing driven by strong O-H...O=C hydrogen bonds, leading to infinite chains in the crystal structure.
Didierjean
Claude
C
Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques (LCM3B), UMR No. 7036, Groupe Biocristallographie, Université Henri Poincaré, Nancy I, Faculté des Sciences,BP 239, 54506 Vandoeuvre lès Nancy CEDEX, France.
Marin
Julien
J
Wenger
Emmanuel
E
Briand
Jean Paul
JP
Aubry
André
A
Guichard
Gilles
G