Synthesis of novel adamantyl and homoadamantyl-substituted β-hydroxybutyric acids

Mol Divers. 2013 Nov;17(4):817-26. doi: 10.1007/s11030-013-9481-7. Epub 2013 Sep 17.

Abstract

Several new adamantyl and homoadamantyl-substituted [Formula: see text]-hydroxybutyric acids, 2-[2-(1-adamantyl)ethyl]-3-hydroxybutyric acid (2), 2-(3-homoadamantyl)-3-hydroxybutyric acid (3), and 2-(1-homoadamantyl)-3-hydroxybutyric acid (4), analogues of the 2-(1-adamantyl)-3-hydroxybutyric acid (1), have been prepared as mixtures of diastereoisomers using selective reduction of corresponding [Formula: see text]-keto esters or aldol condensation of the corresponding carboxylic acid and acetaldehyde. The rearrangement of adamantylmethyl and 3-homoadamantyl groups provided entry to both 3-homoadamantyl and 1-homoadamantyl-substituted hydroxy acids 3 and 4, respectively. The relative configurations of diastereoisomers 3 and 4 have been determined by NMR spectroscopy comparing the values of coupling constants. Adamantyl-substituted [Formula: see text]-hydroxybutyric acid 2 has also been prepared in enantiomerically pure form by Evan's asymmetric synthesis and the absolute configuration has been determined by X-ray crystallography. Contrary to the long-chain acid 2, the attempt to prepare short-chain hydroxy acids 1 and 4 by the same method failed indicating pronounced sensitivity of the used method to the vicinity of the bulky cage group.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Hydroxybutyric Acid / chemical synthesis*
  • 3-Hydroxybutyric Acid / chemistry
  • Combinatorial Chemistry Techniques
  • Models, Molecular
  • Molecular Conformation
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Stereoisomerism

Substances

  • 3-Hydroxybutyric Acid