4-[5-(4-Pentyloxyphenyl)isoxazol-3-yl]benzoic acid
[CAS# 179162-55-1]

Identification

• Classification: Chemical reagent >> Organic reagent >> Ether
• Name: 4-[5-(4-Pentyloxyphenyl)isoxazol-3-yl]benzoic acid
• Molecular Formula: C₂₁H₂₁NO₄
• Molecular Weight: 351.40
• CAS Registry Number: 179162-55-1
• SMILES: CCCCCOC1=CC=C(C=C1)C2=CC(=NO2)C3=CC=C(C=C3)C(=O)O

Properties

• Solubility: Insoluble (1.1E^-3 g/L) (25 °C), Calc.^*
• Density: 1.176±0.06 g/cm³ (20 °C 760 Torr), Calc.^*
• Boiling point: 555.6±50.0 °C 760 mmHg (Calc.)^*
• Flash point: 289.8±30.1 °C (Calc.)^*
• Index of refraction: 1.57 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P305+P351+P338

Discovery and Applications

4-$5-(4-Pentyloxyphenyl)isoxazol-3-yl$benzoic acid is a synthetic aromatic compound that incorporates both a benzoic acid moiety and an isoxazole ring substituted with a pentyloxyphenyl group. Its molecular formula is C₁₉H₁₉NO₄, and its structure represents a convergence of multiple functional components: a carboxylic acid, a heteroaromatic ring, and a lipophilic alkylated phenyl group.

The core of the molecule is the isoxazole ring, a five-membered heterocycle containing one nitrogen and one oxygen atom at non-adjacent positions. The isoxazole is substituted at the 3-position with a 4-carboxyphenyl group, giving the molecule its benzoic acid functionality. At the 5-position, the ring is attached to a 4-pentyloxyphenyl group, in which a five-carbon straight-chain alkoxy group is para-substituted on a phenyl ring. This substituent contributes significant hydrophobicity to the molecule, influencing its solubility, membrane permeability, and potential biological activity.

Compounds containing isoxazole rings are widely studied in medicinal and agrochemical research due to their stability and their ability to participate in a wide range of biological interactions. The isoxazole ring can mimic amide or ester groups in some contexts and can participate in hydrogen bonding and π-stacking interactions. Its incorporation into drug-like molecules often leads to enhanced metabolic stability and improved pharmacokinetic profiles.

The benzoic acid group in this compound offers a site for potential ionic interaction and hydrogen bonding, making it a useful pharmacophore for receptor binding or enzyme inhibition. The carboxylic acid group can also serve as a synthetic handle for further derivatization into esters, amides, or bioconjugates.

The presence of a pentyloxy group para to the isoxazole attachment on the phenyl ring introduces a long, flexible alkyl chain, which can enhance lipophilicity and facilitate membrane association or interaction with hydrophobic pockets in biological targets. The specific 4-substitution pattern promotes linearity and symmetry in molecular binding models, which is often desirable in the design of ligands and inhibitors.

This compound may be synthesized through a cycloaddition reaction between hydroxylamine derivatives and β-keto esters or enones, forming the isoxazole core, followed by functional group manipulations to introduce the aryl and carboxylic acid substituents. Alkylation of the phenol with 1-bromopentane or similar reagents yields the pentyloxy side chain.

In medicinal chemistry, similar compounds have been investigated for anti-inflammatory, antimicrobial, anticancer, and central nervous system activities. The combination of isoxazole and benzoic acid functionalities in a single molecule allows for exploration of binding to a wide variety of biological targets, including enzymes, receptors, and nucleic acids.

Physically, 4-$5-(4-pentyloxyphenyl)isoxazol-3-yl$benzoic acid is expected to be a crystalline solid with moderate melting point. It is likely soluble in organic solvents such as dimethyl sulfoxide, methanol, and chloroform, but only sparingly soluble in water due to the hydrophobic alkyl chain. The compound may exhibit UV absorbance in the 250–300 nm range due to its conjugated aromatic and heteroaromatic systems.

In summary, 4-$5-(4-pentyloxyphenyl)isoxazol-3-yl$benzoic acid is a multifunctional heteroaromatic compound with potential for applications in medicinal and materials chemistry. Its structural features combine polar and nonpolar elements, offering a balance of solubility, reactivity, and biological relevance.

References

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