Exatecan Intermediate 1 (compound 6) is an intermediate of Exatecan. Exatecan is an anticancer agent that is a camptothecin analogue. Exatecan inhibits tumor growth by interfering with the proliferation and division of tumor cells by interacting with DNA. Exatecan is primarily used in research into a variety of cancers including ovarian, lung and breast cancer.

Physicochemical Properties

Molecular Formula	C13H13NO5
Molecular Weight	263.25
Exact Mass	263.079
CAS #	110351-94-5
Related CAS #	(rac)-Exatecan Intermediate 1;102978-40-5;(R)-Exatecan Intermediate 1;110351-91-2;Exatecan Intermediate 1-d5;1346617-23-9
PubChem CID	10220900
Appearance	Off-white to yellow solid-liquid Mixture
Density	1.5±0.1 g/cm3
Boiling Point	666.6±55.0 °C at 760 mmHg
Flash Point	357.0±31.5 °C
Vapour Pressure	0.0±4.6 mmHg at 25°C
Index of Refraction	1.637
LogP	-0.94
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	1
Heavy Atom Count	19
Complexity	574
Defined Atom Stereocenter Count	1
SMILES	O1C([C@](C([H])([H])C([H])([H])[H])(C2C([H])=C3C(C([H])([H])C([H])([H])N3C(C=2C1([H])[H])=O)=O)O[H])=O
InChi Key	IGKWOGMVAOYVSJ-ZDUSSCGKSA-N
InChi Code	InChI=1S/C13H13NO5/c1-2-13(18)8-5-9-10(15)3-4-14(9)11(16)7(8)6-19-12(13)17/h5,18H,2-4,6H2,1H3/t13-/m0/s1
Chemical Name	(4S)-4-ethyl-4-hydroxy-7,8-dihydro-1H-pyrano[3,4-f]indolizine-3,6,10-trione
Synonyms	110351-94-5; (S)-4-ETHYL-4-HYDROXY-7,8-DIHYDRO-1H-PYRANO[3,4-F]INDOLIZINE-3,6,10(4H)-TRIONE; (4S)-4-Ethyl-7,8-dihydro-4-hydroxy-1H-pyrano[3,4-f]indolizine-3,6,10(4H)-trione; (4S)-4-Ethyl-4-hydroxy-7,8-dihydro-1H-pyrano[3,4-f]indolizine-3,6,10-trione; MFCD09833229; (4S)-4-Ethyl-7,8-dihydro-4-hydroxy-1H-pyrano(3,4-f)indolizine-3,6,10(4H)-trione; IGKWOGMVAOYVSJ-ZDUSSCGKSA-N; Exatecan Intermediate 1;
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Topoisomerase
ln Vitro	Provided are an intermediate for synthesizing a camptothecin derivative, a preparation method therefor, and the use thereof. An intermediate A can be obtained from 3-fluoro-4-methylaniline by means of acylation, bromination, and cross-coupling reactions. The intermediate A can be used for preparing an intermediate B to further prepare exatecan mesylate. The intermediate compound B can be obtained from the intermediate A by means of a rearrangement reaction, and exatecan mesylate can be obtained from the intermediate compound B by means of deprotection for acetamido and amino at the ɑ site, a condensation reaction, and a hydrolysis reaction. The reaction starting materials have a low price, the reaction conditions of each step are moderate, the operation is simple, and the yield is high, such that the intermediate is suitable for industrial production [2].
ln Vivo	Antibody-drug conjugates (ADC) using DNA topoisomerase I inhibitor DXd/SN-38 have transformed cancer treatment, yet more effective ADCs are needed for overcoming resistance. We have designed an ADC class using a novel self-immolative T moiety for traceless conjugation and release of exatecan, a more potent topoisomerase I inhibitor with less sensitivity to multidrug resistance (MDR). Characterized by enhanced therapeutic indices, higher stability, and improved intratumoral pharmacodynamic response, antibody-T moiety-exatecan conjugates targeting HER2, HER3, and TROP2 overcome the intrinsic or treatment resistance of equivalent DXd/SN-38 ADCs in low-target-expression, large, and MDR+ tumors. T moiety-exatecan ADCs display durable antitumor activity in patient-derived xenograft and organoid models representative of unmet clinical needs, including EGFR ex19del/T790M/C797S triple-mutation lung cancer and BRAF/KRAS-TP53 double-mutant colon cancer, and show synergy with PARP/ATR inhibitor and anti-PD-1 treatment. High tolerability of the T moiety-exatecan ADC class in nonhuman primates supports its potential to expand the responding patient population and tumor types beyond current ADCs. Significance: ADCs combining a novel self-immolative moiety and topoisomerase I inhibitor exatecan as payload show deep and durable response in low-target-expressing and MDR+ tumors resistant to DXd/SN-38 ADCs without increasing toxicity. This new class of ADCs has the potential to benefit an additional patient population beyond current options. See related commentary by Gupta et al., p. 817. This article is highlighted in the In This Issue feature, p. 799 [1]. We herein report the development and evaluation of a novel HER2-targeting antibody-drug conjugate (ADC) based on the topoisomerase I inhibitor payload exatecan, using our hydrophilic monodisperse polysarcosine (PSAR) drug-linker platform (PSARlink). In vitro and in vivo experiments were conducted in breast and gastric cancer models to characterize this original ADC and gain insight about the drug-linker structure-activity relationship. The inclusion of the PSAR hydrophobicity masking entity efficiently reduced the overall hydrophobicity of the conjugate and yielded an ADC sharing the same pharmacokinetic profile as the unconjugated antibody despite the high drug-load of the camptothecin-derived payload (drug-antibody ratio of 8). Tra-Exa-PSAR10 demonstrated strong anti-tumor activity at 1 mg/kg in an NCI-N87 xenograft model, outperforming the FDA-approved ADC DS-8201a (Enhertu), while being well tolerated in mice at a dose of 100 mg/kg. In vitro experiments showed that this exatecan-based ADC demonstrated higher bystander killing effect than DS-8201a and overcame resistance to T-DM1 (Kadcyla) in preclinical HER2+ breast and esophageal models, suggesting potential activity in heterogeneous and resistant tumors. In summary, the polysarcosine-based hydrophobicity masking approach allowsfor the generation of highly conjugated exatecan-based ADCs having excellent physicochemical properties, an improved pharmacokinetic profile, and potent in vivo anti-tumor activity [3].
References	[1]. Antibody-Exatecan Conjugates with a Novel Self-immolative Moiety Overcome Resistance in Colon and Lung Cancer. Cancer Discov. 2023 Apr 3;13(4):950-973. [2]. Intermediate for synthesizing camptothecin derivatives using exatecan mesylate and its preparation method and application. China, CN111470998. 2020-07-31. [3]. Exatecan Antibody Drug Conjugates Based on a Hydrophilic Polysarcosine Drug-Linker Platform. Pharmaceuticals (Basel). 2021 Mar 9;14(3):247.

Solubility Data

Solubility (In Vitro)

DMSO : 25 mg/mL (94.97 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.90 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.08 mg/mL (7.90 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.7987 mL	18.9934 mL	37.9867 mL
	5 mM	0.7597 mL	3.7987 mL	7.5973 mL
	10 mM	0.3799 mL	1.8993 mL	3.7987 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.