Crystal structure of β-d,l-allose

Area of Science:

• Carbohydrate chemistry
• Crystallography
• Structural biology

Background:

• Allose is a C-3 epimer of glucose.
• Understanding the crystalline structure of sugars is crucial for their chemical and biological applications.

Purpose of the Study:

• To determine the crystal structure of racemic β-d,l-allose.
• To compare the structural properties of racemic allose with its chiral counterpart.

Main Methods:

• Crystallization of allose from an equimolar mixture of d- and l-allose.
• X-ray crystallography to analyze the crystal structure and conformation.
• Measurement of unit cell parameters and volume.

Main Results:

• Racemic d,l-allose crystallized as the β-pyranose anomer.
• The d-allose (l-allose) moiety adopted a (4)C1 ((1)C4) conformation in the crystal.
• A three-dimensional framework was formed by O-H⋯O hydrogen bonds.
• The cell volume of racemic β-d,l-allose (739.36 ų) was smaller than that of chiral β-d-allose (751.0 ų).

Conclusions:

• The study elucidates the detailed crystal structure of racemic allose.
• The observed difference in cell volume highlights the impact of chirality on crystal packing.
• Findings contribute to the understanding of carbohydrate crystal engineering and polymorphism.