Aniline-d5 | CAS 4165-61-1

OVERVIEW
Aniline-d₅ is the fully deuterated analog of aniline, one of the most fundamental aromatic amines used across organic synthesis, polymer chemistry, and analytical applications. In this isotopically labeled compound, all five aromatic hydrogen atoms are replaced with deuterium, resulting in a +5 Da molecular weight increase without altering the compound’s chemical reactivity, polarity, or physical behavior.

Deuterated aniline is an essential reagent in mass spectrometry, NMR spectroscopy, and pharmaceutical research, providing enhanced analytical precision and enabling detailed investigation of reaction mechanisms and isotope effects. Due to its structural simplicity and widespread industrial relevance, aniline-d₅ serves as a key isotopic standard and metabolic tracer in chemical and biochemical studies.

CHEMICAL INFORMATION

• Name: Aniline-d₅;

• Molecular Formula: C₆D₅NH₂

• Molecular Weight: 98.16 g/mol

• CAS Number: 4165-61-1

• Isotopic Enrichment: ≥ 98 atom % D

• Chemical Class: Deuterated aromatic amine

• Odor: Characteristic aromatic amine odor

• Stability: Stable under normal laboratory conditions; may darken on exposure to air or light

APPLICATIONS  of  Aniline-d5 | CAS 4165-61-1

• Mass Spectrometry & Isotopic Labeling:
  Aniline-d₅ is widely employed as a stable isotope-labeled internal standard in LC-MS and GC-MS analyses for quantifying aniline and related compounds in environmental, industrial, and biological samples. Its isotopic distinction allows accurate calibration and quantitation in isotope dilution assays.

• Pharmaceutical Research & Metabolic Studies:
  Utilized to trace metabolic pathways involving aromatic amines and drug intermediates. Deuterated aniline aids in studying biotransformation reactions, enzymatic N-dealkylation, and amine oxidation processes.

• Synthetic Chemistry:
  Serves as a labeled precursor in the synthesis of deuterated pharmaceuticals, dyes, and agrochemicals, providing isotopic control for structural or mechanistic investigations.

• Kinetic Isotope Effect (KIE) Studies:
  Deuteration of the aromatic ring facilitates exploration of reaction kinetics and substitution mechanisms by altering C–H bond dissociation energies, offering valuable mechanistic insights into electrophilic and nucleophilic aromatic reactions.

• Spectroscopic Applications:
  Deuterium labeling suppresses aromatic proton signals in ¹H NMR spectroscopy, simplifying spectral interpretation. It also enhances molecular identification in ²H NMR and IR spectroscopy, where C–D vibrations can be distinguished from C–H.

ADVANTAGES   of  Aniline-d5 | CAS 4165-61-1

• High isotopic purity ensures reliable analytical results.

• Chemically identical to non-deuterated aniline, maintaining reaction compatibility.

• Ideal for isotope dilution quantification and KIE experiments.

• Non-radioactive and safe for laboratory handling.

• Enhances spectral resolution and quantitative reproducibility in MS and NMR applications.

HANDLING

• Hazards: Toxic by inhalation, ingestion, or skin contact; may cause irritation or methemoglobinemia upon prolonged exposure.

• Precautions: Handle in a fume hood using gloves, goggles, and protective clothing. Avoid open flames and sources of oxidation.

• Storage: Store under inert atmosphere (nitrogen or argon) in a cool, dry, and dark place. Protect from light and air.

• Disposal: Dispose of as hazardous organic waste according to local and institutional regulations.

QUALITY & SPECIFICATION

• Chemical Purity: ≥ 98 %

• Isotopic Enrichment: ≥ 98 atom % D

• Water Content: ≤ 0.5 %

• Analytical Verification: Characterized by ¹H NMR (absence of proton signals), ²H NMR, LC-MS, and IR spectroscopy

• Appearance: Colorless to pale yellow liquid

• Documentation: Supplied with a Certificate of Analysis verifying isotopic enrichment and purity

SUMMARY
Aniline-d₅ (CAS 4165-61-1) is a high-purity, fully deuterated analog of aniline that plays a critical role in analytical chemistry, isotopic labeling, and mechanistic studies. Its consistent chemical behavior, coupled with precise isotopic enrichment, makes it ideal for quantitative MS analysis, NMR research, and pharmaceutical development. Stable, reproducible, and safe to handle, aniline-d₅ is a foundational reagent in modern isotopic and kinetic investigations across academic, industrial, and regulatory laboratories.