7-Amino-2(3H)-benzoxazolone
[CAS# 81282-60-2]

Identification

• Classification: Organic raw materials >> Ketone compound
• Name: 7-Amino-2(3H)-benzoxazolone
• Molecular Formula: C₇H₆N₂O₂
• Molecular Weight: 150.13
• CAS Registry Number: 81282-60-2
• EC Number: 462-910-8
• SMILES: C1=CC(=C2C(=C1)NC(=O)O2)N

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Index of refraction: 1.66 (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
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

7-Amino-2(3H)-benzoxazolone is a heterocyclic compound consisting of a fused benzene and oxazolone ring system with an amino substituent at the seventh position. The oxazolone ring, which contains both nitrogen and oxygen atoms, provides a reactive site for nucleophilic and electrophilic reactions, while the amino group contributes additional nucleophilicity and hydrogen-bonding potential. Compounds of the benzoxazolone family have been studied for their chemical versatility and have been utilized as intermediates in the synthesis of pharmaceuticals, agrochemicals, and functional materials. The structure combines aromatic stability with a reactive heterocyclic motif, which has made 7-amino-2(3H)-benzoxazolone a valuable building block in synthetic chemistry.

The synthesis of 7-amino-2(3H)-benzoxazolone typically involves cyclization of appropriately substituted anthranilic acid derivatives or ortho-aminophenols with isocyanate or carbamoyl reagents. Reaction conditions are adjusted to favor the formation of the oxazolone ring while preserving the amino group at the seventh position. The compound is commonly obtained as a crystalline solid and can be purified through recrystallization or chromatography. The amino functionality remains accessible for further chemical modification, and the oxazolone ring is stable under mild reaction conditions but can participate in targeted ring-opening or substitution reactions when desired.

In organic synthesis, 7-amino-2(3H)-benzoxazolone serves as a versatile intermediate for constructing more complex heterocycles. The amino group can undergo acylation, sulfonylation, or alkylation, while the oxazolone ring can be transformed into amides, hydrazides, or other nitrogen-containing structures. These transformations allow systematic exploration of substitution patterns on the benzoxazolone scaffold and the creation of libraries of derivatives for biological or materials applications. The fused bicyclic system provides rigidity and planarity, which is advantageous in designing molecules with defined three-dimensional geometries.

The compound has been applied in medicinal chemistry research as a precursor to pharmacologically active molecules. Benzoxazolone derivatives have been investigated for activities such as enzyme inhibition, anti-inflammatory effects, and central nervous system modulation. The amino group at the seventh position allows attachment of substituents that can interact with biological targets, while the heterocyclic core contributes to binding specificity and metabolic stability. This makes 7-amino-2(3H)-benzoxazolone a useful scaffold for structure–activity relationship studies and optimization of lead compounds.

In materials chemistry, derivatives of 7-amino-2(3H)-benzoxazolone have been used to explore the synthesis of functional dyes, fluorescent probes, and ligands for coordination chemistry. The conjugated system of the benzene and oxazolone rings, combined with the electron-donating amino group, allows tuning of optical and electronic properties. Such applications take advantage of the chemical stability of the heterocyclic ring and the reactivity of the amino group to generate substituted compounds with desirable photophysical characteristics.

Physically, 7-amino-2(3H)-benzoxazolone is generally a stable solid with moderate solubility in polar organic solvents such as dimethylformamide, ethanol, and acetone. It can be stored under standard laboratory conditions, protected from strong acids or bases that may hydrolyze the oxazolone ring. Its combination of stability and reactivity makes it suitable for multistep synthetic sequences and as a precursor for the preparation of diverse functional derivatives.

Overall, 7-amino-2(3H)-benzoxazolone is a valuable heterocyclic intermediate that combines a fused oxazolone-benzene system with a reactive amino group. Its structural features provide multiple avenues for chemical modification, making it a key building block in the synthesis of biologically active compounds, functional materials, and complex heterocyclic molecules.

References

2011. Reversed-phase TLC study of the lipophilicity of fourteen 1,3-benzoxazol-2(3H)-one derivatives and comparison with isomeric 1,2-benzisoxazol-3(2H)-one analogs. JPC – Journal of Planar Chromatography – Modern TLC, 24(4).
DOI: 10.1556/jpc.24.2011.4.14