Oxiracetam
[CAS 62613-82-5]

Identification

• Classification: API >> Nervous system medication >> Brain metabolism regulating drug
• Name: Oxiracetam
• Synonyms: 4-Hydroxy-2-oxopyrrolidine-N-acetamide
• Molecular Formula: C₆H₁₀N₂O₃
• Molecular Weight: 158.16
• CAS Registry Number: 62613-82-5
• EC Number: 636-370-0
• SMILES: C1C(CN(C1=O)CC(=O)N)O

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Melting point: 165-168 °C (Expl.)
• Boiling point: 494.6±40.0 °C 760 mmHg (Calc.)^*
• Flash point: 252.9±27.3 °C (Calc.)^*
• Index of refraction: 1.57 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319
• Safety Statements: P264-P264+P265-P280-P302+P352-P305+P351+P338-P321-P332+P317-P337+P317-P362+P364

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

Oxiracetam is a synthetic compound belonging to the racetam family of nootropic agents, structurally derived from 2-pyrrolidone (a cyclic lactam). It is one of several modifications of the original racetam scaffold, distinguished by the presence of a hydroxy-substituted pyrrolidone side chain that increases polarity relative to earlier compounds in the class.

The core structure of oxiracetam is based on a 2-oxo-pyrrolidine ring, which is a five-membered cyclic amide (lactam). This ring is a defining feature of all racetam compounds and contributes to their chemical stability and hydrogen-bonding properties. In oxiracetam, this lactam nitrogen is substituted with a side chain containing a secondary alcohol and a methyl group, giving the molecule additional functionality compared with simpler racetams such as piracetam.

The presence of the hydroxyl group in the side chain introduces significant polarity and hydrogen-bonding capability. This functional group can act as both a hydrogen-bond donor and acceptor, influencing solubility and molecular interactions. The hydroxyl group also increases aqueous compatibility relative to more hydrophobic derivatives.

The lactam carbonyl group is highly polarized and serves as a hydrogen-bond acceptor. Amide-like resonance between the nitrogen and carbonyl oxygen stabilizes the ring structure, reducing reactivity under physiological conditions. This structural motif is chemically robust and resistant to hydrolysis under neutral conditions.

Oxiracetam is a chiral molecule due to the presence of a stereogenic center in its hydroxy-substituted side chain. Stereochemistry can influence the molecule’s spatial orientation and may affect binding interactions in biological systems. However, the racetam core itself is not inherently chiral; chirality arises from substitution patterns.

From a physicochemical perspective, oxiracetam is relatively polar compared with many small organic molecules because of its amide and hydroxyl functional groups. This polarity contributes to its solubility in water and other polar solvents. At the same time, the cyclic hydrocarbon backbone provides limited hydrophobic character, allowing some balance between aqueous compatibility and membrane permeability.

The molecule does not contain strongly acidic or basic functional groups, and it is generally neutral under physiological pH conditions. This neutrality influences its distribution and transport properties in biological systems.

Chemically, oxiracetam is stable under normal conditions but can undergo degradation under strong acidic or basic environments due to potential hydrolysis of the lactam ring or side-chain transformations. However, such reactions are not typically significant under standard storage or physiological conditions.

Oxiracetam is part of a broader class of racetams that were developed after piracetam as structural analogues designed to modify potency, pharmacokinetics, and physicochemical properties. These compounds share the common 2-pyrrolidone nucleus but differ in side-chain substitutions that influence polarity, lipophilicity, and molecular behavior.

Overall, oxiracetam is a synthetic pyrrolidone-based compound characterized by a cyclic lactam core and a hydroxy-substituted side chain. Its structural features confer relatively high polarity, hydrogen-bonding capacity, and chemical stability, making it a representative member of the racetam family of compounds.

References

2026. Oxiracetam Improves Cognitive Disorder in AD by Modulating AMPAR Subunits GluA1/GluA2 Kinetics. Cell Biochemistry and Biophysics.
DOI: https://pubmed.ncbi.nlm.nih.gov/41739317

2025. Efficacy and safety of L-oxiracetam on cognitive function in patients with traumatic brain injury: a multicentre, randomised, double-blind, phase 3 clinical trial. Signal Transduction and Targeted Therapy.
DOI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12698704