19β,28-Ep-oxy-18α-olean-3β-ol.

Area of Science:

• Organic Chemistry
• Crystallography
• Computational Chemistry

Background:

• Triterpenes are a class of organic compounds with diverse biological activities.
• Betulin is a natural triterpene found in birch bark.
• Wagner-Meerwein rearrangement is a key reaction in terpene chemistry.

Purpose of the Study:

• To synthesize and characterize a novel 18α-oleanane derivative from betulin.
• To elucidate the crystal structure and molecular conformation of the synthesized triterpene.
• To validate experimental findings using quantum mechanical calculations.

Main Methods:

• Wagner-Meerwein rearrangement using betulin and bismuth triflate (Bi(OTf)3·xH2O).
• X-ray crystallography to determine molecular and crystal structure.
• Quantum-mechanical ab initio Roothan Hartree-Fock calculations.

Main Results:

• Successful synthesis of the C30H50O2 triterpene, an 18α-oleanane derivative.
• Determination of two symmetry-independent molecules in the asymmetric unit with similar structural parameters.
• Observed chair conformations for six-membered rings and envelope conformations for epoxide rings, with trans-fusion.
• Identification of O-H⋯O hydrogen bonds in the crystal structure.
• Computational calculations closely matched experimental bond lengths, angles, and molecular conformation.

Conclusions:

• The synthesized triterpene derivative possesses a well-defined molecular structure and conformation.
• Quantum mechanical calculations provide reliable validation for experimental structural data.
• The study contributes to the understanding of triterpene chemistry and structural analysis.