2-(4-Aminophenyl)-2-hydroxyacetic acid - ≥95% , CAS No.13104-66-0

CAS: 13104-66-0 Cat. No.: A979074 Formula: C₈H₉NO₃ Peso molecolare: 167.160 Numero EC: 849-771-2

GRADE & PURITY ≥95%

Storage

Room temperature

Specifications

Specifiche e purezza

≥95%

Condizioni di conservazione di stoccaggio

Room temperature

Purezza

≥95%

Nomi e identificatori

Sorrisi canonici

C1=CC(=CC=C1C(C(=O)O)O)N

IUPAC Name

2-(4-aminophenyl)-2-hydroxyacetic acid

InChIKey

YJGSMLNQLMZMJD-UHFFFAOYSA-N

INCHI

1S/C8H9NO3/c9-6-3-1-5(2-4-6)7(10)8(11)12/h1-4,7,10H,9H2,(H,11,12)

Peso molecolare

167.160

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Benzenoids
    • Classe Benzene and substituted derivatives
      • Subclass Aniline and substituted anilines

• Kingdom: Organic compounds
• Superclass: Benzenoids
• Classe: Benzene and substituted derivatives
• Subclass: Aniline and substituted anilines
• Intermediate Tree Nodes: Not available
• Direct Parent: Aniline and substituted anilines
• Alternative Parents: Alpha hydroxy acids and derivatives Secondary alcohols Amino acids Monocarboxylic acids and derivatives Carboxylic acids Primary amines Organic oxides Hydrocarbon derivatives Carbonyl compounds Aromatic alcohols
• Molecular Framework: Aromatic homomonocyclic compounds
• Substituents: Aniline or substituted anilines - Alpha-hydroxy acid - Hydroxy acid - Amino acid or derivatives - Amino acid - Secondary alcohol - Carboxylic acid derivative - Carboxylic acid - Monocarboxylic acid or derivatives - Alcohol - Organooxygen compound - Organonitrogen compound - Primary amine - Aromatic alcohol - Hydrocarbon derivative - Organic oxide - Carbonyl group - Organic oxygen compound - Amine - Organic nitrogen compound - Aromatic homomonocyclic compound
• Descrizione: This compound belongs to the class of organic compounds known as aniline and substituted anilines. These are organic compounds containing an aminobenzene moiety.
• External Descriptors: Not available

Data sources

1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.

DOI: 10.1186/s13321-016-0174-y

Proprietà chimiche e fisiche

• Peso molecolare: 167.160 g/mol
• XLogP3: -0.100
• Hydrogen Bond Donor Count: 3
• Hydrogen Bond Acceptor Count: 4
• Rotatable Bond Count: 2
• Exact Mass: 167.058 Da
• Monoisotopic Mass: 167.058 Da
• Topological Polar Surface Area: 83.600 Ų
• Heavy Atom Count: 12
• Formal Charge: 0
• Complexity: 164.000
• Isotope Atom Count: 0
• Defined Atom Stereocenter Count: 0
• Undefined Atom Stereocenter Count: 1
• Defined Bond Stereocenter Count: 0
• Undefined Bond Stereocenter Count: 0
• The total count of all stereochemical bonds: 0
• Covalently-Bonded Unit Count: 1

Application Protocols

No item-specific tested application protocols are provided for this small-molecule reagent. As a general building block, procedures are highly context-dependent (e.g., amide coupling, esterification, diazotization). Refer to the “Reaction Conditions” and “Synthetic Utility” sections for representative literature-style guidance and adjust to your substrates, equipment, and scale.

• If preparing stock solutions: dissolve at appropriate pH (acidic for anilinium salts or basic for carboxylates) or in polar organics (DMF, DMSO, MeOH) to desired concentration, filter sterilize if required for cell-free biochemical assays, and document solvent composition for reproducibility.

For assay-, cell-, or material-specific uses, consult domain-standard protocols and validate with small-scale pilots.

Biological Roles

No item-specific biological data are provided for this product; the following are general notes about the chemical class.

• Structural class: an aromatic amino α-hydroxy acid. Such scaffolds are common in biochemical probe design because they combine hydrogen-bonding capacity and an aniline handle for further derivatization.
• Ionization and transport (general): at physiological pH ranges, the compound may exist in zwitterionic or singly charged forms depending on microenvironment, influencing aqueous solubility and potential interactions with transporters in model systems. These properties are often leveraged in uptake/permeability studies of analogous molecules.
• Enzyme/protein interactions (literature context): α-Hydroxy acids can act as ligands or substrates for dehydrogenases/oxidases after appropriate derivatization; aniline-bearing aromatics are frequently used as affinity tags or photoaffinity precursors following further functionalization.
• Biological derivatization routes: the para-amine allows formation of diazonium species for bioconjugation to activated aromatic residues on surfaces or macromolecules (materials/bioconjugation research). The carboxylate can be converted to NHS esters for coupling to amines on peptides/proteins under mildly basic conditions.

Caution: This product is provided strictly for research use only (per Product Data). No claims of biological activity, safety, or suitability for diagnostic/therapeutic applications are made or implied.

Buffer Applications

This compound is not a standard laboratory buffering agent. While it contains both acidic (carboxyl) and basic (aniline) functionalities, its pKa values and solubility behavior are not optimized for stable, high-capacity buffering across common biological pH ranges.

• Recommendation: Use established buffers (e.g., phosphate, HEPES, MOPS, Tris) for pH control. The present compound may be dissolved in buffered solutions for experimental purposes, but it should not be relied upon to maintain pH.
• Practical note: If preparing solutions, adjust pH with minimal strong acid/base to achieve dissolution as the carboxylate (basic) or anilinium (acidic) salt, then back-adjust to the target pH using a proper buffering system.

Item-specific buffer specs, recipes, and capacities: Not applicable.

Green Alternatives

Greener practice focuses on solvent and reagent choices for transforming this building block rather than replacing the substrate itself.

• Preferred greener solvents (literature/industry guidance):
  • Replace DMF/DMSO where feasible with water, ethanol, 2-MeTHF, MeCN (with caution), or propylene carbonate depending on transformation and solubility.
  • For esterifications, consider solid acid catalysts or enzymatic approaches in green solvents (EtOH, 2-MeTHF) rather than mineral-acid-catalyzed Fischer in toluene.
• Coupling chemistry:
  • Use carbonyldiimidazole (CDI) or ethyl chloroformate alternatives with greener profiles, or enzymatic amidation where compatible.
  • Explore microwave-assisted or solvent-minimized couplings to reduce energy and waste.
• Workup/purification:
  • Favor aqueous crystallizations (EtOH/water) over chlorinated solvent precipitations when possible.
  • Utilize catch-and-release ion-exchange or solid-supported reagents to reduce solvent volumes.

Comparison (general):

• Conventional choices: DMF, DCM, and pyridine are effective but score poorly on health/environment metrics.
• Greener alternatives: water/ethanol systems, 2-MeTHF, and ethyl acetate provide improved EHS profiles, though may require solubility tuning (salt formation, mild heating) and sometimes deliver slower reaction rates.

Note: Selection must balance EHS with reaction efficiency and product quality; pilot small-scale screens to validate alternative conditions for your specific transformation.

Pharmaceutical Uses

No pharmacopeial status, excipient role, or cGMP grade is specified for this item; it is supplied for research use only.

General, non-clinical context (literature/industry practice):

• As a bifunctional building block, 2-(4-aminophenyl)-2-hydroxyacetic acid can be employed in discovery chemistry to construct amide/ester libraries, linkers, and fragments. The para-aniline provides a handle for diazotization or acylation, while the α-hydroxy acid enables modulation of polarity and hydrogen-bonding.
• In process development studies, related α-hydroxy acids are sometimes screened as chiral auxiliaries or resolved to furnish enantioenriched intermediates; any such use requires appropriate specifications not provided here.
• Formulation context: Not a typical excipient. If used as a salt former or intermediate in pre-formulation research, ensure compatibility with target APIs and document residual levels per internal R&D quality standards.

Compliance note: This product is not intended for human or veterinary use, diagnostic purposes, or as an excipient in commercial formulations. Any pharmaceutical-related experimentation should occur under research settings with full analytical characterization and risk assessment.

Physical Properties

• Item-specific specs: Not specified for this item; refer to CoA/Spec Sheet.
• Storage (from Product Data): Room temperature.

Literature/general reference properties for the 2-(4-aminophenyl)-2-hydroxyacetic acid scaffold (for planning only; not product specifications):

• Aggregated physical form: typically a crystalline solid; color can range off-white to tan depending on impurities/oxidation common to anilines.
• Acid–base character: bifunctional; contains a carboxylic acid (pKa ~3–4, literature for α-hydroxy acids) and a para-aniline (pKaH ~4–6 for anilinium, literature) leading to potential zwitterionic behavior near neutral pH.
• Solubility profile (qualitative, literature):
  • Water: low-to-moderate at neutral pH; markedly increased solubility in basic aqueous media (as the carboxylate) and in acidic media (as the anilinium salt); sparing in purely nonpolar solvents.
  • Organics: soluble in polar protic (MeOH, EtOH) and polar aprotic solvents when ion-paired or as esters/salts; limited in hydrocarbons.
• Partitioning: expected low-to-moderate lipophilicity (logP small/negative in ionized states; literature trend for aminomandelates), enabling aqueous handling when pH-adjusted.
• Melting point, density, refractive index, and UV cutoff: Not specified for this item; consult CoA/SDS or primary literature for approximate reference values if needed for method development.

Important: Use the above only as general guidance. For critical process parameters, rely on measured values for this specific lot (CoA).

Quality and Grades

• Item-specific grade/purity, stabilizers, and analytical limits: Not specified for this item; refer to CoA/Spec Sheet.

General guidance on quality considerations for this compound class:

• For use as a building block in synthesis, typical quality attributes may include assay (%), residual solvents, inorganic salts, and limits for related aromatic amines/oxidized species. Request or review CoA chromatograms (HPLC/GC) when selectivity is mission-critical.
• If chiral applications are intended, verify whether the material is racemic or enantioenriched. Aminomandelic acids possess a stereogenic center; optical rotation and enantiomeric excess (ee) may be provided on CoA for resolved grades.
• If used in trace analysis or bioconjugation, consider specifications such as metals and UV-absorbing impurities; absence of such specifications here means they are not controlled for this listing.
• Stabilizers: none indicated for this item. Aromatic amines can slowly oxidize; opaque or amber packaging is preferred. If a stabilizer is present in another lot/grade, it would be declared on the CoA.

Recommendation: Match the grade to your application. For synthetic transformations, a standard research grade often suffices; for sensitive analytical/bioconjugation tasks, inquire about higher-purity or enantioenriched offerings or custom specifications.

Reaction and Applications

This molecule is a versatile bifunctional building block combining an aniline and an α-hydroxycarboxylic acid (aminomandelic acid scaffold):

• Functional handles and typical use-cases (literature/general):
  • Amide/urea formation: Couple the carboxylic acid to amines via EDC·HCl/HOBt, HATU, or CDI to access amides/ureas for medicinal chemistry and probe libraries.
  • Esterification/derivatization: Fischer esterification (MeOH, acid catalyst) or alkyl chloroformates afford esters and carbonates, improving solubility for further transformations.
  • Protecting group strategies: Protect the aniline as Boc, Cbz, or Ac to prevent side reactions in acylations or oxidations. The α-OH can be protected as silyl ethers (TBS) or benzyl ethers when orthogonality is needed.
  • Diazotization/azo coupling (aniline): Generate diazonium salts (NaNO2, HX, 0–5 °C) for Sandmeyer-type substitutions or azo dye formation onto activated aromatics, enabling rapid scaffold diversification.
  • Oxidation/reduction: Benzylic α-OH can be oxidized to the corresponding keto acid (e.g., Dess–Martin, Swern) or reduced/derivatized to diols/ethers.
• Application domains:
  • Fragment and linker synthesis: The para-amino group enables conjugation to electrophiles; the acid enables bioconjugation via NHS esters.
  • Chirality: If enantioenriched, it serves as a chiral auxiliary or precursor; racemates can be resolved via diastereomeric salt formation.
• Practical tips:
  • Adjust pH to control solubility during couplings (slightly basic conditions often improve dissolution and reactivity).
  • Avoid strong oxidants unless desired; anilines can darken on exposure to air/light. Conduct diazotizations cold and under acidic conditions to stabilize diazonium intermediates.

Reaction Conditions

General, literature-informed conditions for typical transformations of this scaffold (for planning only; optimize per substrate and do not treat as specifications):

• Amide coupling (carboxyl to amide):
  • Solvent: DMF or MeCN; co-solvent DCM/DMF for solubility.
  • Reagents: HATU or EDC·HCl (1.1–1.5 eq) with HOBt/HOAt or Oxyma; base DIPEA (2–3 eq).
  • Temperature: 0–25 °C; time: 1–16 h. Typical literature yields: 60–90% depending on partner and protection state.
• Esterification (Fischer):
  • Solvent: corresponding alcohol (MeOH, EtOH) with catalytic H2SO4 or p-TsOH; Dean–Stark not required for lower alcohols.
  • Temperature: reflux; time: 2–24 h. Neutralize and recrystallize.
• Acid chloride formation:
  • Reagent: SOCl2 (2–4 eq) or (COCl)2 with DMF catalytic; solvent: DCM or toluene.
  • Temperature: 0–25 °C, then gentle reflux if needed. Protect aniline beforehand.
• α-OH oxidation to α-keto acid:
  • Dess–Martin periodinane in DCM (0–25 °C, 1–3 h) or Swern (oxalyl chloride/DMSO, −78 to 0 °C, 1–2 h) with non-nucleophilic base (Et3N).
• Diazotization/azo coupling (aniline):
  • Generate diazonium with NaNO2 in 2–4 M HCl at 0–5 °C; couple to activated aromatics in mildly basic media (pH 8–10) at 0–10 °C, monitoring by TLC/UV.
• Protection strategies:
  • Boc protection: Boc2O (1.1–1.5 eq), base (NaHCO3 or DIPEA), solvent: dioxane/water or MeCN, 0–25 °C.
  • TBS protection of α-OH: TBSCl, imidazole, DMF, 0–25 °C, 2–6 h.

Notes:

• Control pH/ionization for solubility; pre-form salts if necessary.
• Anilines may oxidize; conduct sensitive steps under inert atmosphere and subdued light.

Safety and Handling

• GHS/SDS (item-specific): Not specified for this item; refer to the product SDS for authoritative hazard classification, H-statements, and pictograms.
• General hazards (literature/analogous materials):
  • Aniline derivatives may cause skin/eye irritation and can be harmful if inhaled or ingested; avoid dust formation and inhalation.
  • Organic acids are irritants; acidic solutions may cause mucous membrane irritation.
• Recommended PPE and controls (good laboratory practice):
  • Wear lab coat, safety glasses, and suitable chemical-resistant gloves (e.g., nitrile). Handle in a fume hood to avoid inhalation of dust or aerosols.
  • Avoid contact with strong oxidizers (anilines can be oxidized), strong reducing agents, and acylating/chlorinating reagents unless under controlled synthetic conditions.
• First aid (overview; defer to SDS):
  • Inhalation: move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: rinse with water for several minutes; remove contaminated clothing; obtain medical advice for persistent irritation.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical attention.
• Fire and thermal decomposition:
  • Organic solid; use water fog, CO2, dry chemical, or foam to extinguish. Decomposition may release nitrogen oxides and carbon oxides.
• Handling tips:
  • Minimize exposure to air and light to limit slow oxidative discoloration of the aniline moiety.
  • For solution work, adjust pH thoughtfully to control ionization and solubility; avoid generating aerosols.

Always consult the official SDS supplied with the product for definitive safety and response guidance.

Solvent Selection

As a bifunctional aromatic α-hydroxycarboxylic acid bearing a para-aniline, solubility is highly pH- and ionization-dependent.

• Polarity class (general): polar, H-bond donor/acceptor capable; forms salts that are water-soluble.
• Miscibility/solubility trends (literature/general):
  • Water: enhanced solubility upon deprotonation (carboxylate) or protonation (anilinium). Adjust pH accordingly for aqueous processes.
  • Alcohols (MeOH, EtOH): good solvency, especially when warmed or with small amounts of base/acid to form salts or esters in situ.
  • Polar aprotics (DMF, DMSO, NMP): dissolve well as neutral molecules or salts; useful for coupling chemistry.
  • Aprotic, low-polarity (DCM, EtOAc, MTBE, hydrocarbons): limited solubility; use as biphasic extraction solvents post-neutralization/ion-pairing or after derivatization (esters, amides) to increase lipophilicity.

Practical selection guidance:

• For amide/peptide couplings: DMF, DCM/DMF mixtures, or MeCN with a base (DIPEA) are common. If solubility is poor, add a co-solvent (DMSO, NMP) or convert to the methyl/ethyl ester.
• For salt formation/purification: use aqueous acid (e.g., HCl) to form the soluble anilinium salt, or mild base (NaHCO3, Na2CO3) for carboxylate formation; back-extract into organics after neutralization.
• For crystallizations: ethanol/water or isopropanol/water mixtures often provide control over polymorph and purity (optimize by small-scale screen).

Comparison note:

• Relative to unsubstituted mandelic acid, the para-amino group offers additional salt-handling flexibility and formation of ion pairs, often simplifying aqueous workups.

Storage and Reconstitution

• Storage (from Product Data): Room temperature. Store tightly capped in a dry place. Protect from light and air to minimize slow oxidation/discoloration of the aniline functionality.
• Shipping: Not specified for this item; refer to CoA/Spec Sheet.

General handling and reconstitution guidance (non-specification):

• Solid handling: keep container tightly closed; consider a desiccator for long-term bench storage. If hygroscopic behavior is observed, dry under vacuum at ambient temperature before use.
• Solution preparation:
  • Aqueous: dissolve by pH adjustment to form the carboxylate (mild base) or anilinium (dilute acid). Avoid strong bases/acids if downstream reactions are base/acid sensitive.
  • Organic: for highest concentrations, use DMF, DMSO, or alcohols; gently warm (≤40 °C) and sonicate if needed. Record final solvent composition.
• Stock solutions: prepare aliquots to avoid repeated freeze–thaw. For DMSO/DMF stocks, store at 2–8 °C or −20 °C depending on stability requirements of your workflow; bring to room temperature before opening to minimize moisture uptake.
• Stability monitoring: inspect periodically for color changes or precipitation; if discoloration occurs, re-purify (e.g., recrystallization) or prepare fresh solutions.

Always defer to the product label and SDS for authoritative storage and handling instructions.

Structure and Identity

A para-aminophenyl-substituted α-hydroxyacetic acid (an aminomandelic acid analogue) featuring both an aniline and an α-hydroxycarboxylic acid functional motif.

• Item-specific identifiers (from Product Data):
  • Product Name: 2-(4-Aminophenyl)-2-hydroxyacetic acid
  • CAS: 13104-66-0
  • CID: 18003691
  • InChIKey: 438740 (as provided; format appears truncated — consult CoA/SDS for the authoritative identifier)
• Structural description (literature/general):
  • The molecule comprises a para-aminophenyl ring (p-aniline) bonded at the benzylic position to a tertiary carbon bearing a hydroxyl (–OH) and a carboxylic acid (–CO2H) group, i.e., Ar–C(OH)–CO2H with the amine at the 4-position of the aromatic ring.
  • Key functional groups: primary aniline (–NH2), α-hydroxy acid motif (–CHOH–CO2H), and para-substituted benzene.
  • Stereochemistry: the α-carbon is a stereogenic center; commercial material may be racemic unless otherwise stated. For this item, optical purity is Not specified for this item; refer to CoA/Spec Sheet.
• Computed/literature identifiers (non-item-specific; for reference only):
  • Typical SMILES (literature): NC1=CC=C(C=C1)C(O)C(=O)O
  • Typical InChIKey (literature) for 4-aminomandelic acid analogues differs from the item’s provided key; use the Product Data/CoA for the definitive key.
• Elemental formula and mass (literature): C8H9NO3, MW ≈ 167.16 g/mol (reference value; not a specification of this lot).

Synthetic Utility

The molecule integrates three reactive elements: an aniline, a benzylic α-hydroxyl, and a carboxylic acid, enabling orthogonal diversification.

• Carboxylic acid manifold:
  • Amide formation: EDC/HOBt, HATU, T3P, or CDI couplings to access amides, ureas, and carbamates. Pre-activation as acid chloride (SOCl2, oxalyl chloride) is also possible with prior amine protection to avoid undesired acylation/rearrangement.
  • Ester formation: Fischer esterification (ROH, catalytic acid) or via DCC/DMAP for mild conditions. Subsequent manipulations (hydrogenolysis, transesterification) can modulate lipophilicity.
• α-Hydroxyl manifold:
  • Oxidation to keto acid (e.g., DMP, Swern) for accessing α-keto acid chemistry (e.g., Strecker-type additions, decarboxylative couplings).
  • Etherification or carbonate formation to tune stability/solubility; silyl protection (TBS, TBDPS) provides orthogonality with acid/amine manipulations.
• Aniline manifold:
  • Protection strategies: Boc/Cbz/Ac to tame nucleophilicity during acid chloride formation or oxidative steps.
  • Diazotization/Sandmeyer to introduce halo, CN, or heteroatom substituents at the para position (via diazonium) or to form azo linkages to phenols/anilines.
  • Electrophilic acylation/sulfonylation to generate amides/sulfonamides (e.g., acyl chlorides, sulfonyl chlorides) as stable conjugation points.
• Orthogonal planning:
  • Protect the most reactive site first (often the aniline), then manipulate the acid/α-OH. Employ chemoselective reagents (e.g., CDI for acid activation while the aniline is protected) to minimize side products.

This versatility makes the compound a useful hub for constructing diverse analogues in medicinal and materials chemistry.

Target Specificity

Not applicable. This product is a small-molecule reagent/building block, not a biologic or affinity reagent. No antigen/epitope, species reactivity, clone, or isotype information is relevant or provided.