Methyl 2-oxoindole-6-carboxylate
[CAS# 14192-26-8]

Identification

• Classification: Organic raw materials >> Heterocyclic compound >> Indoles
• Name: Methyl 2-oxoindole-6-carboxylate
• Synonyms: 6-Methoxycarbonyl-2-oxindole; Oxindole-6-carboxylic acid methyl ester
• Molecular Formula: C₁₀H₉NO₃
• Molecular Weight: 191.18
• CAS Registry Number: 14192-26-8
• EC Number: 687-964-1
• SMILES: COC(=O)C1=CC2=C(CC(=O)N2)C=C1

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Boiling point: 388.1±42.0 °C 760 mmHg (Calc.)^*
• Flash point: 188.5±27.9 °C (Calc.)^*
• Index of refraction: 1.573 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H317
• Safety Statements: P261-P264-P270-P272-P280-P301+P317-P302+P352-P321-P330-P333+P317-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

Methyl 2-oxoindole-6-carboxylate is a heteroaromatic compound derived from the indole scaffold, a bicyclic structure consisting of a benzene ring fused to a pyrrole moiety. In this molecule, the indole core is modified by the presence of a carbonyl group at the 2-position (yielding a 2-oxoindole, also known as an oxindole) and a carboxylate ester substituent at the 6-position. These structural features make the compound a valuable intermediate in organic synthesis and medicinal chemistry.

The oxindole framework is widely recognized in natural products and synthetic pharmaceuticals. Compounds with this scaffold exhibit diverse biological activities, ranging from anticancer and antimicrobial effects to enzyme inhibition. The introduction of an ester group at the 6-position enhances the versatility of methyl 2-oxoindole-6-carboxylate, allowing further modification through hydrolysis, amidation, or ester-exchange reactions. Such transformations can generate derivatives with distinct physicochemical properties and biological profiles.

The discovery and development of oxindole derivatives trace back to studies on natural products containing indole and oxindole motifs, such as alkaloids and plant-derived bioactive molecules. Synthetic chemists have since explored oxindole esters as intermediates in the construction of more complex heterocyclic frameworks. The ester group at the 6-position provides a convenient handle for diversification, making this compound particularly suitable for library synthesis in drug discovery.

In practical applications, methyl 2-oxoindole-6-carboxylate is often employed as a building block in medicinal chemistry programs. Its structural features allow it to serve as a precursor to kinase inhibitors, protease inhibitors, and other therapeutic agents targeting protein-protein interactions. The oxindole moiety itself is known to mimic peptide backbones, enabling it to bind to biologically relevant sites. Derivatives of this compound have been investigated for their potential roles in anticancer therapy, particularly due to their ability to interfere with signaling pathways regulated by kinases.

Beyond medicinal applications, oxindole esters like methyl 2-oxoindole-6-carboxylate are also of interest in synthetic methodology. Their reactivity includes enolate chemistry at the 3-position, nucleophilic substitution reactions involving the ester group, and oxidative or reductive transformations at various sites of the indole ring. This versatility makes them valuable intermediates in the preparation of structurally diverse heterocycles.

Research in recent years has increasingly focused on functionalizing oxindole derivatives for use in supramolecular chemistry and materials science. The rigid, conjugated structure of the indole core contributes to electronic properties that can be exploited in molecular recognition and in the development of optoelectronic materials. The carboxylate functionality provides opportunities for anchoring the molecule to surfaces or for incorporation into polymeric frameworks.

In summary, methyl 2-oxoindole-6-carboxylate is a synthetic oxindole ester that combines the bioactive potential of the indole skeleton with the synthetic versatility of an ester substituent. Its discovery stems from ongoing investigations into oxindole chemistry, and its applications are primarily as a precursor in medicinal chemistry and organic synthesis. The compound continues to be of interest in the design of bioactive molecules, the study of reaction mechanisms, and the exploration of heterocyclic frameworks in materials and supramolecular science.