Donepezil
[CAS 120014-06-4]

Identification

• Classification: API >> Nervous system medication >> Brain metabolism regulating drug
• Name: Donepezil
• Synonyms: 2-[(1-Benzyl-4-piperidyl)methyl]-5,6-dimethoxy-2,3-dihydroinden-1-one
• Molecular Formula: C₂₄H₂₉NO₃
• Molecular Weight: 379.49
• CAS Registry Number: 120014-06-4
• EC Number: 601-651-9
• SMILES: COC1=C(C=C2C(=C1)CC(C2=O)CC3CCN(CC3)CC4=CC=CC=C4)OC

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Melting point: 207 °C (Expl.)
• Boiling point: 527.9±50.0 °C 760 mmHg (Calc.)^*
• Flash point: 273.1±30.1 °C (Calc.)^*
• Solubility: water: 2.931 mg/L, acetone: ~25 mg/mL, DMSO: 10 mMl (Expl.)
• Index of refraction: 1.578 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS06;GHS07 Danger
• Risk Statements: H300-H302-H315-H319-H335-H413
• Safety Statements: P261-P264-P264+P265-P270-P271-P273-P280-P301+P316-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	2	H300
Acute toxicity	Acute Tox.	1	H300
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2A	H319

chemBlink Chemical Story

Donepezil, CAS 120014-06-4, is a centrally acting reversible acetylcholinesterase inhibitor. Its chemical story is best understood by looking at how its structure creates function rather than by treating the name as a simple catalog label. The molecule or material combines a dimethoxyindanone region joined to an N-benzylpiperidine, a combination that explains its relevance to symptomatic treatment of dementia of the Alzheimer's type.

Eisai researchers led by Hachiro Sugimoto reported that random screening first found an N-benzylpiperazine lead with cholinergic activity. Replacing piperazine with N-benzylpiperidine greatly increased anti-acetylcholinesterase activity, and further structure-activity work led to an indanone series and E2020, later named donepezil. By reversibly inhibiting acetylcholinesterase, donepezil prolongs acetylcholine signaling.

The free base is CAS 120014-06-4; the medicine is commonly supplied as donepezil hydrochloride, CAS 120011-70-3. U.S. prescribing information states that donepezil hydrochloride is indicated for Alzheimer's-type dementia, with efficacy demonstrated in mild, moderate and severe disease. The treatment is symptomatic rather than curative.

A broader lesson follows from this example. Chemical identity is only the starting point for performance. In polymers and surfactants, composition, molecular distribution and formulation can dominate behavior; in synthetic intermediates, the value may lie in transformations that occur only in later steps; in biologically active compounds, mechanism must be separated from clinical evidence. For Donepezil, the most reliable interpretation is therefore the one supported by its documented chemistry and literature rather than an assumed application.

The compound also illustrates why specialty chemicals often look more complicated than their job description suggests. Functional groups are selected to solve different parts of a practical problem: one region may provide reactivity, another solubility or interfacial affinity, and another stability or a controllable breaking point. Once those roles are separated, the long chemical name becomes a map of molecular design.

References:
Sugimoto H et al. Yakugaku Zasshi. 1999;119:101-113. DOI: 10.1248/yakushi1947.119.2_101; Sugimoto H et al. Curr Med Chem. 2000;7:303-339. PMID: 10637367; PubChem, Donepezil, CID 3152; DailyMed, Donepezil hydrochloride tablets, updated 2026.

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