trans-1,2-Cyclopentanedicarboxylic acid
[CAS# 1461-97-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty acid
• Name: trans-1,2-Cyclopentanedicarboxylic acid
• Molecular Formula: C₇H₁₀O₄
• Molecular Weight: 158.15
• CAS Registry Number: 1461-97-8 (80656-14-0)
• EC Number: 215-962-9
• SMILES: C1C[C@H]([C@@H](C1)C(=O)O)C(=O)O

Properties

• Density: 1.4±0.1 g/cm³, Calc.^*
• Melting point: 163-165 ºC (Expl.)
• Index of Refraction: 1.535, Calc.^*
• Boiling Point: 378.6±35.0 ºC (760 mmHg), Calc.^*
• Flash Point: 196.9±22.4 ºC, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H312-H332
• Precautionary Statements: P261-P264-P270-P271-P280-P301+P317-P302+P352-P304+P340-P317-P321-P330-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332

Discovory and Applicatios

trans-1,2-Cyclopentanedicarboxylic acid is an organic compound with the molecular formula C₇H₁₀O₄, consisting of a cyclopentane ring substituted with two carboxylic acid groups at the 1 and 2 positions in a trans configuration. This specific geometric arrangement places the two carboxylic groups on opposite sides of the cyclopentane ring plane, a feature that influences both its physical properties and chemical behavior compared to its cis isomer. It is one of the well-known stereoisomers of 1,2-cyclopentanedicarboxylic acid, alongside the corresponding cis form.

The compound can be synthesized by controlled oxidation of suitable trans-configured precursors. A commonly reported method involves the oxidation of trans-1,2-dimethylcyclopentane or trans-1,2-cyclopentanediol using strong oxidizing agents such as nitric acid or potassium permanganate under carefully regulated conditions. The stereospecificity of the starting material is preserved through the oxidation step, yielding the desired trans-dicarboxylic acid. The separation of the trans isomer from the cis counterpart can be achieved using crystallization or chromatographic techniques, as the two forms exhibit different solubility and melting point profiles.

trans-1,2-Cyclopentanedicarboxylic acid is primarily of interest in synthetic organic chemistry, where it is employed as a dicarboxylic acid building block. The presence of two carboxylic acid groups enables its use in condensation reactions with diols and diamines to form polyesters and polyamides. In such polymerizations, the spatial arrangement of the carboxyl groups impacts the resulting polymer architecture and its mechanical and thermal properties. Polymers incorporating the trans isomer may exhibit differing degrees of rigidity and crystallinity compared to those derived from the cis isomer, due to differences in backbone conformation.

The compound has also been studied in the context of coordination chemistry. The two carboxyl groups, when deprotonated, can function as bidentate ligands capable of chelating metal ions. Metal complexes formed with trans-1,2-cyclopentanedicarboxylate ligands have been characterized with transition metals such as copper(II), cobalt(II), and nickel(II). The structural attributes of these complexes have been investigated using X-ray crystallography and spectroscopic methods to better understand ligand coordination behavior and metal-ligand geometries.

In the field of medicinal chemistry, derivatives of 1,2-cyclopentanedicarboxylic acid, including the trans isomer, have been explored as intermediates in the synthesis of biologically active compounds. These studies have focused on modifying the carboxylic acid functionalities through esterification, amidation, or formation of heterocyclic rings. The resulting derivatives have been evaluated for pharmacological activity, although the base compound itself is not known to exhibit direct therapeutic effects.

trans-1,2-Cyclopentanedicarboxylic acid is also of interest for physicochemical studies involving conformational analysis and intramolecular interactions. Its rigid five-membered ring and the fixed spatial orientation of its functional groups make it suitable for investigating the relationship between molecular geometry and reactivity. Techniques such as nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy have been used to characterize the molecule. In IR spectroscopy, characteristic absorptions are observed for the carboxylic acid C=O stretching and O-H bending modes, while NMR data provide confirmation of the trans configuration through coupling constants and chemical shift patterns.

The solid-state properties of trans-1,2-cyclopentanedicarboxylic acid include relatively high melting point and limited solubility in nonpolar solvents, which are consistent with the presence of strong hydrogen bonding interactions between carboxylic acid groups. It is generally more stable in solid form and can be stored under standard laboratory conditions without significant degradation. Its sodium and potassium salts can be formed by neutralization with the corresponding hydroxides and have been used in studies of ionic interactions and salt crystallization.

trans-1,2-Cyclopentanedicarboxylic acid remains a compound of continued interest in synthetic chemistry, coordination chemistry, and materials science. Its defined stereochemistry, bifunctional reactivity, and conformational rigidity support its use as a versatile intermediate for both academic research and applied chemical development.

References

2014. Safety Risk Categorization of Organic Extractables Associated with Polymers used in Packaging, Delivery and Manufacturing Systems for Parenteral Drug Products. Pharmaceutical Research, 31(11).
DOI: 10.1007/s11095-014-1523-z

2011. One-Dimensional Hydrogen-Bonded Infinite Chain from Nickel(II) Tetraaza Macrocyclic Complex and 1,2-Cyclopentanedicarboxylate Ligand. International Journal of Molecular Sciences, 12(4).
DOI: 10.3390/ijms12042232

1990. Mechanism and inhibition of prolidase. The Journal of biological chemistry, 265(32).
DOI: 10.1016/s0021-9258(17)45415-9