Exatecan Intermediate 2
[CAS 182182-31-6]

Identification

• Classification: Organic raw materials >> Amino compound >> Amide compound
• Name: Exatecan Intermediate 2
• Synonyms: N-(8-Amino-6-fluoro-5-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)acetamide
• Molecular Formula: C₁₃H₁₅FN₂O₂
• Molecular Weight: 250.27
• CAS Registry Number: 182182-31-6
• SMILES: CC1=C(C=C(C2=C1CCC(C2=O)NC(=O)C)N)F

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Boiling point: 550.1±50.0 °C 760 mmHg (Calc.)^*
• Flash point: 286.5±30.1 °C (Calc.)^*
• Index of refraction: 1.575 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319
• Safety Statements: P501-P270-P264-P280-P302+P352-P337+P313-P305+P351+P338-P362+P364-P332+P313-P301+P312+P330

chemBlink Chemical Story

Some pharmaceutical intermediates become interesting only when their place in a larger molecular story is recognized. Exatecan Intermediate 2, CAS 182182-31-6, is N-(8-amino-6-fluoro-5-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)acetamide, a fluorinated tetralone derivative used in synthetic routes toward exatecan-related chemistry.

Exatecan belongs to the camptothecin family of topoisomerase I inhibitors. Camptothecin itself is a natural-product scaffold whose fused ring system can trap the transient DNA-topoisomerase I cleavage complex. When the enzyme attempts to relieve torsional stress in DNA, camptothecin-type inhibitors stabilize an otherwise short-lived covalent intermediate; collisions with replication machinery then turn this trapped state into DNA damage. Exatecan was developed as a potent, more soluble camptothecin analog, but as a freely administered cytotoxic drug its therapeutic window was limited.

The later importance of exatecan chemistry came from a different strategy: do not simply make the poison stronger - deliver a related payload more selectively. Daiichi Sankyo researchers developed DXd, or deruxtecan, as an exatecan-derived topoisomerase I inhibitor suitable for antibody-drug conjugates. In an ADC, an antibody recognizes a tumor-associated target while a linker carries a highly potent small-molecule payload. This design helped make exatecan-derived chemistry central to modern oncology. Trastuzumab deruxtecan and datopotamab deruxtecan are examples of approved ADCs using DXd-class payload technology.

That history gives an otherwise obscure intermediate a more memorable identity. The amino, fluoro, methyl, ketone, and acetamide functions in Exatecan Intermediate 2 are not there because the compound itself is intended to be a drug. They are part of a staged construction of a much more elaborate polycyclic pharmacophore. Process chemists need intermediates such as this to introduce the correct substitution pattern before later ring-forming, stereochemical, and functional-group transformations.

The molecule therefore illustrates an important feature of pharmaceutical manufacturing: a clinically important drug technology may depend on compounds that never appear on a medicine label. Their value is architectural. Exatecan Intermediate 2 is one of the pieces used to reach a family of topoisomerase I payloads whose significance expanded dramatically when potent cytotoxic chemistry was combined with targeted antibody delivery.

References:
1. PubChem, N-(8-Amino-6-fluoro-5-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)acetamide, CID 10220585.
2. Ogitani Y. et al. Bioorg Med Chem Lett. 2016, 26, 5069-5072. DOI: 10.1016/j.bmcl.2016.08.082.
3. Conilh L. et al. Pharmaceuticals. 2021, 14, 247. PMCID: PMC8000490.
4. Payload-Based Clinical Pharmacology Review of Approved Antibody-Drug Conjugates. Clin Pharmacol Ther. 2026.

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