Uncategorized
Phenacetin: Chemical Profile, CAS Number, History, Toxicology & Analytical Methods
Phenacetin is a historical analgesic compound studied in pharmaceutical chemistry, toxicology, analytical science, and chemical safety research. It is also known by synonyms such as acetophenetidin, p-ethoxyacetanilide, and N-(4-ethoxyphenyl)acetamide.
This chemical profile reviews phenacetin’s CAS number, molecular formula, structure, historical background, toxicology profile, analytical identification methods, and research relevance.
General Information
| Property | Value |
|---|---|
| Chemical Name | Phenacetin |
| Common Synonyms | Acetophenetidin, p-ethoxyacetanilide, N-(4-ethoxyphenyl)acetamide |
| CAS Number | 62-44-2 |
| PubChem CID | 4754 |
| Molecular Formula | C10H13NO2 |
| Molecular Weight | 179.22 g/mol |
| IUPAC Name | N-(4-ethoxyphenyl)acetamide |
| Chemical Class | Acetanilide derivative |
| Historical Category | Analgesic and antipyretic compound |
| Research Context | Toxicology, analytical chemistry, pharmaceutical history, forensic chemistry |
Chemical Identity
Phenacetin is an acetanilide derivative with an ethoxy-substituted aromatic ring and an acetamide functional group. Its chemical identity is important in pharmaceutical history because it was once used as an analgesic and antipyretic compound before safety concerns changed its regulatory status in many countries.
For accurate documentation, phenacetin should be identified by its CAS number, molecular formula, IUPAC name, synonyms, structure, Safety Data Sheet, Certificate of Analysis, and analytical method records.
For background on chemical identifiers, see our guide to What Is a CAS Number?.
Chemical Structure Overview
Phenacetin contains several important structural features:
- Aromatic benzene ring
- Ethoxy group
- Acetamide group
- Para-substituted anilide structure
- Acetanilide-related backbone
The ethoxy group and acetamide structure help distinguish phenacetin from related analgesic compounds and metabolites. These structural features are also useful in analytical chemistry when comparing spectra, retention behavior, molecular weight, and chemical database records.
Phenacetin Synonyms and Naming
Phenacetin appears under many names in chemical databases and older pharmaceutical literature. Common synonyms include acetophenetidin, p-ethoxyacetanilide, acetophenetidine, phenacetine, and N-(4-ethoxyphenyl)acetamide.
Synonym review is important because older pharmaceutical names, database names, and systematic chemical names may all refer to the same compound. However, researchers should still verify the CAS number and structure before assuming that two records describe the same substance.
Historical Background
Phenacetin has historical importance as one of the earlier synthetic analgesic and antipyretic compounds. It was introduced into medical use in the late nineteenth century and later appeared in analgesic mixtures in several markets.
Over time, toxicology and epidemiology research raised serious concerns about phenacetin-containing products. These concerns included kidney damage, urinary tract cancer associations, and broader safety issues linked to repeated exposure in analgesic mixtures.
Today, phenacetin is mainly discussed in scientific, historical, toxicological, forensic, and analytical contexts rather than as a modern therapeutic compound.
Phenacetin and Pharmaceutical History
Phenacetin is often studied as part of the history of analgesic development. It belongs to the broader group of acetanilide-related compounds that helped shape early pharmaceutical chemistry.
Its history is scientifically important because it shows how compounds once used in medicine can later become important toxicology case studies. Phenacetin also illustrates why long-term safety evaluation, pharmacovigilance, regulatory review, and chemical documentation matter in pharmaceutical science.
Pharmacology Overview
Phenacetin was historically associated with analgesic and antipyretic activity. In scientific literature, it is often discussed alongside related compounds and metabolites, especially acetaminophen.
A high-level pharmacology review may consider:
- Historical analgesic use
- Antipyretic activity
- Metabolic conversion
- Relationship to acetanilide chemistry
- Safety concerns from repeated exposure
- Toxicological outcomes
- Regulatory withdrawal history
This article does not provide clinical guidance, dosing information, or use instructions.
Metabolism and Research Relevance
Phenacetin is relevant in metabolism research because it is associated with metabolic conversion to other compounds, including acetaminophen. This relationship has made phenacetin useful in pharmacology, toxicology, and drug-metabolism discussions.
Researchers may study phenacetin in relation to:
- Historical drug metabolism
- Enzyme activity research
- Toxicology pathways
- Analytical detection
- Metabolite identification
- Pharmaceutical safety history
Metabolism discussions should remain scientific and should not be presented as use guidance.
Analytical Identification
Phenacetin can be evaluated using several analytical chemistry techniques. The appropriate method depends on the research objective, sample matrix, required sensitivity, and documentation standard.
Common analytical approaches include:
- HPLC
- LC-MS
- GC-MS
- NMR spectroscopy
- FTIR spectroscopy
- UV-Visible spectroscopy
- Melting point comparison
- Reference standard comparison
For an external chemical identity reference, see the PubChem phenacetin record.
Phenacetin in Analytical Chemistry
Phenacetin is relevant to analytical chemistry because it can appear in reference libraries, historical pharmaceutical studies, forensic research, toxicology screening, and method validation contexts.
Analytical review may focus on:
- Identity confirmation
- Retention behavior
- Mass spectral data
- Infrared spectral data
- UV-Visible absorption data
- Impurity profiling
- Degradation studies
- Reference standard comparison
Reliable identification should compare the CAS number, molecular formula, molecular weight, IUPAC name, synonyms, structure, retention time, and spectral data.
Toxicology Overview
Phenacetin has a significant toxicology profile. Scientific and regulatory literature has linked phenacetin and phenacetin-containing analgesic mixtures to serious health concerns, especially involving the urinary tract and kidneys.
A toxicology review may consider:
- Renal toxicity
- Analgesic nephropathy
- Urinary tract cancer associations
- Metabolic activation
- Long-term exposure concerns
- Historical analgesic mixture use
- Epidemiological findings
- Animal study evidence
- Regulatory review
Phenacetin is not appropriate for casual product-style wording. It should be discussed in neutral scientific language focused on identity, toxicology, analytical detection, and historical safety evaluation.
Carcinogenicity and Safety Review
Phenacetin has been evaluated in carcinogenicity literature. Scientific reviews have associated phenacetin and phenacetin-containing analgesic mixtures with cancers of the renal pelvis and ureter.
This safety history makes phenacetin an important compound for toxicology education. It also shows why a chemical profile should separate historical use, analytical identity, toxicological evidence, and current regulatory considerations.
Safety Data and Documentation
Phenacetin documentation should be reviewed carefully because older names, historical product mixtures, and modern chemical records can create confusion.
Useful documents include:
- Safety Data Sheet
- Certificate of Analysis
- CAS record
- Chemical database entry
- Analytical method data
- Toxicology literature
- Regulatory records
- Reference standard documentation
A Safety Data Sheet may provide hazard and handling information. A Certificate of Analysis may provide batch-specific testing data. Neither document should be used alone as a complete scientific identity record.
Regulatory Considerations
Phenacetin’s regulatory status depends on country, context, formulation, and intended use. In many modern settings, phenacetin is discussed as a withdrawn or restricted pharmaceutical substance and as a toxicology concern.
Researchers should verify applicable laws, institutional policies, supplier documentation, SDS records, and regulatory database information before making any compliance decision.
Regulatory discussion should remain neutral and should not include buying, sourcing, or use guidance.
Information-Gain Section: Phenacetin vs Acetaminophen
Phenacetin and acetaminophen are related in pharmaceutical history, but they should not be treated as the same chemical.
Phenacetin is an ethoxy-substituted acetanilide derivative. Acetaminophen, also known as paracetamol, is a hydroxy-substituted acetanilide derivative. This structural difference matters in metabolism, toxicology, analytical identification, and regulatory history.
For chemical documentation, researchers should verify the exact compound rather than relying on broad historical relationships between analgesic compounds.
Common Misunderstandings About Phenacetin
Phenacetin is sometimes misunderstood because it appears in older pharmaceutical literature, chemical databases, toxicology reports, and forensic contexts.
Common misunderstandings include:
- Treating phenacetin and acetaminophen as identical
- Ignoring older synonyms in historical literature
- Assuming historical use means modern approval
- Treating an SDS as proof of purity
- Ignoring COA batch documentation
- Confusing phenacetin with analgesic mixtures
- Assuming regulatory status is the same everywhere
- Using database identity without checking structure
A responsible chemical profile should separate identity, history, toxicology, analytical methods, and regulation.
Frequently Asked Questions
What is phenacetin?
Phenacetin is a historical analgesic and antipyretic compound studied today mainly in pharmaceutical history, toxicology, analytical chemistry, and regulatory science.
What is the CAS number for phenacetin?
The CAS number for phenacetin is 62-44-2.
What is the molecular formula of phenacetin?
The molecular formula of phenacetin is C10H13NO2.
What is the molecular weight of phenacetin?
Phenacetin has a molecular weight of about 179.22 g/mol.
What is the IUPAC name of phenacetin?
The IUPAC name is N-(4-ethoxyphenyl)acetamide.
What are common synonyms for phenacetin?
Common synonyms include acetophenetidin, p-ethoxyacetanilide, phenacetine, acetophenetidine, and N-(4-ethoxyphenyl)acetamide.
Is phenacetin related to acetaminophen?
Phenacetin and acetaminophen are related in pharmaceutical history and metabolism research, but they are different chemical compounds.
Why is phenacetin important in toxicology?
Phenacetin is important because toxicology and epidemiology literature have linked it and phenacetin-containing analgesic mixtures to serious kidney and urinary tract safety concerns.
What analytical methods may be used for phenacetin?
Common methods include HPLC, LC-MS, GC-MS, NMR, FTIR, UV-Visible spectroscopy, melting point comparison, and reference standard comparison.
Is phenacetin still used as a modern medicine?
Phenacetin is generally discussed today as a historical, withdrawn, restricted, or toxicology-relevant compound rather than as a modern therapeutic substance.
Why should researchers verify phenacetin synonyms?
Researchers should verify synonyms because phenacetin appears under many historical, database, and systematic names.
What documents should researchers review?
Researchers should review the SDS, COA, CAS record, chemical database entry, toxicology literature, analytical method records, and regulatory documents.
References
- PubChem Phenacetin
- NIST Chemistry WebBook Phenacetin
- NCBI Bookshelf / IARC Phenacetin Evaluation
- National Toxicology Program Report on Carcinogens
- Scientific literature on phenacetin toxicology and analgesic history
