| Field | Specification |
|---|---|
| Alternative names | Naphthol AS-E phosphate |
| CAS no. | |
| Applications | |
| Molecular weight | |
| Molecular formula | C17H13ClNO5P |
| Purity | |
| SMILES | |
| Form | Solid |
| Storage | |
| Shipping | |
| Catalog no. (Mfr.) | |
| Main SKU |
Compound Overview
KG-501, also known as Naphthol AS-E phosphate, is a CREB inhibitor with an IC50 of 6.89 μM. It is supplied as a white to light yellow solid (C17H13ClNO5P, MW 377.72) at 99.45% purity.
Physical & Chemical Properties
| CAS Number | 18228-17-6 |
|---|---|
| Molecular Formula | C17H13ClNO5P |
| Molecular Weight | 377.72 g/mol |
| Purity | 99.45% |
| Appearance | Solid |
| Color | White to light yellow |
| SMILES | O=C(C1=C(OP(O)(O)=O)C=C2C=CC=CC2=C1)NC3=CC=C(Cl)C=C3 |
| Signaling Pathway | Epigenetics |
| Solubility | In Vitro: DMSO: 6 mg/mL (15.88 mM; Requires sonication and warming; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO) |
| Storage | Powder: -20°C, 3 years; 4°C, 2 years. In solvent: -80°C, 6 months; -20°C, 1 month. |
| Shipping | Room temperature in continental US; may vary elsewhere. |
Biological Activity
IC50 & Target
IC50: 6.89 μM (CREB)[1].
Literature Cited
Sources cited in this description and in the In Vitro & In Vivo Data tab. Peer-reviewed publications that used this product are listed under References.
Safety
For Research Use Only. Not for use in diagnostic or therapeutic procedures, and not for human or veterinary use. Handle in accordance with the Safety Data Sheet and your institution's chemical hygiene plan.
In Vitro
| Solvent | Solubility | Notes |
|---|---|---|
| DMSO | 6 mg/mL (15.88 mM) | requires sonication and warming; use freshly opened DMSO (absorbed moisture lowers solubility) |
Aliquot the stock solution and store it at -80°C (up to 6 months) or -20°C (up to 1 month); avoid repeated freeze-thaw cycles.
In Vivo
Choose the formulation that suits the animal model and route of administration; percentages are volume ratios of the final working solution. Start from a clear DMSO stock (see In Vitro above), add the co-solvents one at a time in the order listed, mixing after each addition, and prepare the working solution fresh on the day of dosing. If precipitation or phase separation occurs, gentle warming or sonication can help.
Protocol 1
| Composition | 10% DMSO + 40% PEG300 + 5% Tween-80 + 45% saline |
|---|---|
| Result | ≥ 2 mg/mL (5.29 mM); clear solution |
| How to prepare | Gives a clear solution at ≥ 2 mg/mL (saturation not determined). For 1 mL of working solution: add 100 μL DMSO stock (20.0 mg/mL) to 400 μL PEG300; then 50 μL Tween-80; then 450 μL saline to bring the volume to 1 mL. Saline: dissolve 0.9 g sodium chloride in ddH2O and make up to 100 mL. |
Protocol 2
| Composition | 10% DMSO + 90% (20% SBE-β-CD in saline) |
|---|---|
| Result | ≥ 2 mg/mL (5.29 mM); suspension |
| How to prepare | Gives a suspension at ≥ 2 mg/mL (saturation not determined). The suspension is suitable for oral and intraperitoneal dosing. For 1 mL of working solution: add 100 μL DMSO stock (20.0 mg/mL) to 900 μL 20% SBE-β-CD in saline. 20% SBE-β-CD in saline: dissolve 2 g SBE-β-CD powder in 10 mL saline until clear (4°C, store up to one week). |
Protocol 3
| Composition | 10% DMSO + 90% Corn Oil |
|---|---|
| Result | ≥ 2 mg/mL (5.29 mM); clear solution |
| How to prepare | Gives a clear solution at ≥ 2 mg/mL (saturation not determined). Use with caution if continuous dosing will exceed two weeks. For 1 mL of working solution: add 100 μL DMSO stock (20.0 mg/mL) to 900 μL corn oil. |
Data provided by the manufacturer.
In Vitro
KG-501 directly targets the KIX domain of CBP, which disrupts the CREB-CBP complex and inhibits both CREB-target gene induction and IL-1β-mediated angiogenic activity in NSCLC[1]. Binding of phospho (Ser-133) CREB to KIX is disrupted by KG-501 (Ki of ~90 μM), with CREB concentrations kept within the linear range of the binding assay. In HEK293T cells, KG-501 also blocks forskolin induction of the endogenous CREB target genes NR4A2, αCG, c-fos, and RGS2, pointing to a likely general effect of KG-501 on CREB activity[2]. Because NF-κB likewise relies on CBP as a cofactor for regulating gene expression, KG-501 can also inhibit NF-κB transcription activity. HUVEC migration induced by CM from A549 cells is significantly lower when those A549 cells were treated with IL-1β plus 10 μM KG-501 than with IL-1β alone. KG-501 at 10 μM suppresses expression of every IL-1β–induced CXC chemokine gene apart from CXCL8. Secretion of CXCL5 protein induced by IL-1β is significantly suppressed by KG-501, and similar effects of KG-501 are seen in the H1734 cell line[3].
Data provided by the manufacturer. Numbered citations refer to the Literature Cited list in the product description.
Need this compound in a format that drops straight into your assay? We can tailor formulation, chemistry, and documentation so your results stay consistent across runs and re-orders.
- Format options: solid or pre-dissolved solution (choose solvent), target concentration, aliquots, light/moisture-protected packaging
- Chemistry options: free base/acid vs salt forms, hydrate/solvate preference, stereoisomer control (single enantiomer or racemate), close analogs
- Add-on labels & handles: D/¹³C/¹⁵N isotopes (LC-MS/internal standards), azide/alkyne or other functional handles for conjugation
- QC & documentation: standard COA or enhanced analytical pack (HPLC/LC-MS/NMR), chiral purity, residual solvents, water content (KF), method-specific specs
- Scale & continuity: mg to gram scale, bulk pricing, lot reservation, repeat-order continuity
To quote quickly, tell us: compound name + CAS/structure (SMILES or mol file), intended assay context, solvent preference, salt/stereochemistry requirements, purity/QC level, and the amount (mg–g).
Can’t find the compound you’re looking for?
Send the CAS or structure and your specs. We can help source it, suggest close equivalents, or discuss custom synthesis with the right QC documentation (RUO).
Adv Funct Mater. 2023 Jan 20.
CREB1-driven CXCR4hi neutrophils promote skin inflammation in mouse models and human patients. Nat Commun 2023 Sep 22;14(1):5894. PMID: 37736772
Areca nut-induced metabolic reprogramming and M2 differentiation promote OPMD malignant transformation. J Exp Clin Cancer Res 2024 Aug 20;43(1):233. PMID: 39160581
Placentation Disruption by Perfluorooctanoic Acid and Perfluorooctanesulfonate in Human Trophoblast Organoids. Environ Sci Technol 2025 Sep 30;59(38):20263-20275. PMID: 40954114
Receptor activity-modifying protein 1 regulates mouse skin fibroblast proliferation via the Gαi3-PKA-CREB-YAP axis. Cell Commun Signal 2022 Apr 12;20(1):52. PMID: 35413847
Isotalatizidine, a C19-diterpenoid alkaloid, attenuates chronic neuropathic pain through stimulating ERK/CREB signaling pathway-mediated microglial dynorphin A expression. J Neuroinflammation 2020 Jan 10;17(1):13. PMID: 31924228
Sympathetic Neurostress Drives Osteoblastic Exosomal MiR-21 Transfer to Disrupt Bone Homeostasis and Promote Osteopenia. Small Methods 2022 Mar;6(3):e2100763. PMID: 35312228
Dexamethasone attenuates neuropathic pain through spinal microglial expression of dynorphin A via the cAMP/PKA/p38 MAPK/CREB signaling pathway. Brain Behav Immun 2024 Jul:119:36-50. PMID: 38555991
Epimedium brevicornum Maxim and Ligustrum lucidum Ait enhance glucocorticoid-associated anti-inflammatory effects in asthma via the cAMP/PKA/CREB signaling pathway. J Ethnopharmacol 2026 May 10:362:121259. PMID: 41690429
Proteomic analysis reveals that cigarette smoke exposure diminishes ovarian reserve in mice by disrupting the CREB1-mediated ovarian granulosa cell proliferation-apoptosis balance. Ecotoxicol Environ Saf 2024 Feb:271:115989. PMID: 38242047
