Tenulin 0.25-hydrate, a sesquiterpene lactone isolated from Helenium amarum

Area of Science:

• Natural Product Chemistry
• Crystallography
• Organic Chemistry

Background:

• Tenulin is a natural product isolated from Helenium amarum.
• Understanding the crystal structure of natural products is crucial for elucidating their properties and potential applications.

Purpose of the Study:

• To determine the crystal structure of the title compound, C17H22O5·0.25H2O.
• To analyze the hydrogen bonding interactions within the crystal lattice.

Main Methods:

• Single-crystal X-ray diffraction was used to analyze the crystal structure.
• The asymmetric unit was characterized, revealing two independent tenulin molecules and a water molecule.

Main Results:

• The crystal structure contains two independent tenulin molecules (A and B) and a water molecule of crystallization.
• Hydrogen bonds (O-H⋯O) between tenulin and water molecules form layered structures parallel to the ac plane.
• The hemiketal hydroxyl group is in the β-position, and water molecules mediate interactions between tenulin molecules.

Conclusions:

• The study provides detailed insights into the supramolecular arrangement of tenulin hydrate in the solid state.
• The hydrogen bonding network highlights the specific interactions governing the crystal packing.
• This structural information contributes to the understanding of natural product chemistry and crystallography.