Hexahydro-5-hydroxy-4-(hydroxymethyl)-2H-cyclopenta[b]furan-2-one
[CAS 521323-11-5]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Lactone and oxygen-containing heterocyclic compound >> Furan and pyran
• Name: Hexahydro-5-hydroxy-4-(hydroxymethyl)-2H-cyclopenta[b]furan-2-one
• Synonyms: 5-hydroxy-4-(hydroxymethyl)-3,3a,4,5,6,6a-hexahydrocyclopenta[b]furan-2-one
• Molecular Formula: C₈H₁₂O₄
• Molecular Weight: 172.18
• CAS Registry Number: 521323-11-5
• SMILES: C1C(C(C2C1OC(=O)C2)CO)O

Properties

• Solubility: Soluble (36 g/L) (25 °C), Calc.^*
• Density: 1.365±0.06 g/cm³ (20 °C 760 Torr), Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2016 ACD/Labs)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319
• Safety Statements: P501-P270-P264-P280-P302+P352-P337+P313-P305+P351+P338-P362+P364-P332+P313-P301+P312+P330

Discovery and Applications

Hexahydro-5-hydroxy-4-(hydroxymethyl)-2H-cyclopenta[b]furan-2-one is a saturated polycyclic lactone that belongs to the family of oxygen-containing bicyclic compounds derived from cyclopentane-fused furanone frameworks. Structurally, it consists of a cyclopentane ring fused to a lactone (cyclic ester) system, with additional hydroxyl and hydroxymethyl substituents that significantly increase its polarity and hydrogen-bonding capacity.

The core structural motif is a cyclopenta[b]furan-2-one system, which is a bicyclic lactone framework. Lactones are cyclic esters formed by intramolecular esterification of hydroxy acids, and they are widely encountered in natural products and synthetic intermediates. The presence of the carbonyl group in the lactone ring introduces electrophilic character at the carbonyl carbon, making such systems susceptible to nucleophilic ring-opening reactions under acidic or basic conditions.

The “hexahydro” designation indicates that the bicyclic system is fully saturated, meaning that no double bonds remain in the ring framework. This saturation increases conformational flexibility compared with aromatic or unsaturated analogues. As a result, the molecule can adopt multiple puckered conformations, influenced by steric interactions and hydrogen bonding between substituents.

Two hydroxyl-containing substituents are present on the ring system: a hydroxyl group at position 5 and a hydroxymethyl group at position 4. These functional groups contribute significantly to the compound’s polarity and ability to form intermolecular hydrogen bonds. The hydroxymethyl group introduces a primary alcohol functionality, which can participate in oxidation reactions to form aldehydes or carboxylic acids, or undergo esterification under suitable conditions. The secondary hydroxyl group can similarly engage in derivatization or oxidation chemistry.

The combination of a lactone and multiple alcohol functionalities suggests that the compound is highly reactive in functional group transformation chemistry. Lactones can be hydrolyzed to the corresponding hydroxy acids, while hydroxyl groups provide additional sites for chemical modification. This makes such structures useful as intermediates in synthetic organic chemistry, particularly in the construction of more complex oxygenated frameworks.

From an electronic perspective, the lactone carbonyl group is the most electrophilic center in the molecule. The adjacent oxygen atom in the ring exerts both inductive and resonance effects, stabilizing the cyclic ester but also activating it toward nucleophilic attack under appropriate conditions. The presence of electron-donating hydroxyl groups elsewhere in the molecule can influence the overall electron distribution, although their effects are localized due to the saturated nature of the ring system.

Hydrogen bonding plays a major role in determining the physical properties of this compound. The presence of two hydroxyl groups allows for both intramolecular and intermolecular hydrogen bonding, which can influence boiling point, melting point, and solubility. In aqueous or polar solvent environments, these interactions generally enhance solubility due to favorable interactions with solvent molecules.

Compounds containing fused lactone systems similar to cyclopenta[b]furanones are frequently encountered in natural product chemistry, particularly in plant-derived metabolites and biosynthetic intermediates. While not all such structures are directly bioactive, their frameworks often serve as precursors or simplified analogues of biologically active molecules.

In terms of physicochemical behavior, hexahydro-5-hydroxy-4-(hydroxymethyl)-2H-cyclopenta[b]furan-2-one is expected to be a polar, non-aromatic compound with moderate aqueous solubility. Its solubility and reactivity are strongly influenced by the hydrogen-bonding network formed by its hydroxyl groups and the polarity of the lactone functionality.

Overall, this compound is a saturated bicyclic lactone bearing multiple oxygenated substituents, characterized by significant polarity and functional group diversity. Its chemical significance lies in its lactone reactivity and the presence of multiple hydroxyl groups, making it a versatile intermediate in oxygenated organic synthesis and structural elaboration of bicyclic frameworks.