7-Ethyl-10-hydroxycamptothecin
[CAS 86639-52-3]

Identification

• Classification: API >> Antineoplastic agents >> Natural source antineoplastic agents
• Name: 7-Ethyl-10-hydroxycamptothecin
• Synonyms: 4,11-Diethyl-4,9-dihydroxy-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione
• Molecular Formula: C₂₂H₂₀N₂O₅
• Molecular Weight: 392.40
• CAS Registry Number: 86639-52-3
• EC Number: 643-093-9
• SMILES: CCC1=C2CN3C(=CC4=C(C3=O)COC(=O)[C@@]4(CC)O)C2=NC5=C1C=C(C=C5)O

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*
• Boiling point: 810.3±65.0 °C 760 mmHg (Calc.)^*
• Flash point: 443.8±34.3 °C (Calc.)^*
• Solubility: DMSO 20 mg/mL, Water <1 mg/mL, Ethanol <1 mg/mL (Expl.)
• Index of refraction: 1.738 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS06;GHS08 Danger
• Risk Statements: H301-H341
• Safety Statements: P203-P264-P270-P280-P301+P316-P318-P321-P330-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	3	H301
Germ cell mutagenicity	Muta.	2	H341
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Reproductive toxicity	Repr.	1B	H360
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	3	H331
Germ cell mutagenicity	Muta.	1B	H340
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319

chemBlink Chemical Story

7-Ethyl-10-hydroxycamptothecin is better known as SN-38, the active metabolite responsible for much of the antitumor activity of irinotecan. Camptothecin was isolated in the 1960s from Camptotheca acuminata, but direct development was complicated by solubility and toxicity. Medicinal chemistry produced derivatives including irinotecan, a clinically useful prodrug. Carboxylesterases convert irinotecan to SN-38 in the body. PubChem identifies SN-38 as C22H20N2O5 and a DNA topoisomerase I inhibitor. It stabilizes the normally transient topoisomerase I-DNA cleavage complex; collision with replication machinery can then produce damaging DNA lesions. SN-38 is substantially more potent than irinotecan in cellular systems, making its formation and subsequent glucuronidation central to irinotecan efficacy, variability and toxicity.

The exact registry identity matters because free forms, salts, hydrates, stereoisomers, metabolites, intermediates and finished medicines can have separate CAS numbers even when their names are closely related. This distinction affects molecular weight, analytical standards, formulation, manufacturing specifications and interpretation of published data. A reliable database story therefore follows the exact substance rather than silently borrowing every property of a related compound.

Structure also shows how chemists use functional groups as deliberate tools. Aromatic and heterocyclic frameworks establish molecular shape and electronics, while amines, hydroxyl groups, carbonyls, carboxyl functions or ionic centers determine reactivity and intermolecular interactions. In multistep synthesis, a compound may be valuable precisely because one position can be transformed selectively while the rest of a complex framework survives.

Modern development is also an analytical-control problem. Researchers must establish identity and purity, distinguish relevant stereoisomers or salt forms, monitor process-related species and define reproducible specifications. These requirements explain why an intermediate, metabolite or reagent can be scientifically important even when it is never administered as an independent medicine.

A Chemical Story must distinguish documented use from structural possibility. A familiar scaffold may suggest an activity, but resemblance is not evidence that the exact CAS substance has been tested or approved for that purpose. Verified history and demonstrated applications therefore take priority over attractive but unsupported extrapolation.

Seen broadly, practical performance emerges from the entire molecular system rather than one recognizable group. Structure, stereochemistry, physical form, synthetic route, metabolism and reaction environment can all determine what a substance actually does. Connecting those molecular details to its documented role is what turns a registry entry into a meaningful chemical story.

The exact registry identity matters because free forms, salts, hydrates, stereoisomers, metabolites, intermediates and finished medicines can have separate CAS numbers even when their names are closely related. This distinction affects molecular weight, analytical standards, formulation, manufacturing specifications and interpretation of published data. A reliable database story therefore follows the exact substance rather than silently borrowing every property of a related compound.

Structure also shows how chemists use functional groups as deliberate tools. Aromatic and heterocyclic frameworks establish molecular shape and electronics, while amines, hydroxyl groups, carbonyls, carboxyl functions or ionic centers determine reactivity and intermolecular interactions. In multistep synthesis, a compound may be valuable precisely because one position can be transformed selectively while the rest of a complex framework survives.

Modern development is also an analytical-control problem. Researchers must establish identity and purity, distinguish relevant stereoisomers or salt forms, monitor process-related species and define reproducible specifications. These requirements explain why an intermediate, metabolite or reagent can be scientifically important even when it is never administered as an independent medicine.

References:
1. PubChem. 7-Ethyl-10-Hydroxycamptothecin (SN-38), CID 104842.
2. Mathijssen RHJ et al. Clinical pharmacokinetics and metabolism of irinotecan. Clin Cancer Res.
3. Wall ME et al. Isolation and structure of camptothecin. J Am Chem Soc. 1966.

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