## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: In Vitro Enzyme Inhibitory Activity: Samples:Controls: Gefitinib, erlotinib hydrochloride, purchased from Anqing worldchem Co., LTD.; lapatinib ditosylate, purchased from Taizhou Xingcheng Chempharm Co., Ltd.; CI-1033 hydrochloride, purchased from Shanghai hanxiangchem, Co., Ltd.; andThe present compounds: lab-made, their chemical names and structural formulae are shown in the preparation examples.Assay Procedures:The abbreviations used in the following assay have the following meanings:HEPES: hydroxyethyl piperazine ethanesulfonic acid;Brij-35: polyoxyethylene lauryl ether;DTT: dithiothreitol;Coating Reagent #3: #3 coating agent;EDTA: ethylene diamine tetraacetic acid, purchased from Sigma Co. Ltd.;FAM labeled peptide: fluorescein labeled peptide 22 (GL Biochem);ATP: adenosine triphosphate (Sigma);DMSO: dimethyl sulfoxide;EGFR: human epidermal growth factor receptor (Carna);HER2: human epidermal growth factor receptor 2 (Carna);HER4: human epidermal growth factor receptor 4 (Carna).1. Formulating the agents to be used in the assay(1) 1.25-fold MnCl2-free kinase buffer (62.5 mM HEPES, PH 7.5, 0% Brij-35, 12.5 mM MgCl2, 2.5 mM DTT);(2) 1.25-fold MnCl2-containing kinase buffer (62.5 mM HEPES, pH 7.5, 0% Brij-35, 12.5 mM MgCl2, 12.5 mM MnCl2, 2.5 mM DTT);(3) Stop buffer (100 mM HEPES, pH 7.5, 0.01% Brij-35, 0.2% Coating Reagent #3, 50 mM EDTA);(4) 2.5-fold kinase solutions (to the 1.25-fold kinase buffers were added the corresponding kinases to formulate 2.5-fold EGFR, HER2, HER4 kinase solutions);(5) 2.5-fold peptide solutions (to the 1.25-fold kinase buffers were added FAM labeled peptide and ATP to formulate the peptide solutions);(6) 5-fold compound solutions (using 100% DMSO to formulate 50-fold compound solutions having different concentration gradients, and diluting with water by 10 times to obtain 5-fold compound solutions having different concentration gradients);2. Adding 5 μL of a 5-fold compound solution to a 384-well plate;3. Adding 10 μL of a 2.5-fold kinase solution to incubate for 10 min;4. Then adding 10 μL of a 2.5-fold peptide solution, and reacting at 28° C. for 1 h; and5. Finally, adding 25 μL of stop buffer to terminate the reaction, and reading the data with Caliper.6. Curve fitting to obtain an IC50 value.The calculated inhibition ratio (%)=(the maximum conversion rate−the conversion rate)/(the maximum conversion rate−the minimum conversion rate)×100The curve fitting was conducted with the Xlfit software to obtain IC50 values.
- Assay organism: Homo sapiens
- Target name: Epidermal growth factor receptor
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: COc1cc2ncnc(Nc3ccc(F)c(Cl)c3)c2cc1OCCCN1CCOCC1
- Properties:
- ChEMBL ID: CHEMBL939
- Preferred name: GEFITINIB
- Molecule type: Small molecule
- Max clinical phase: 4
- Molecular weight: 446.91
- Heavy atoms: 31
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 7
- TPSA: 68.74
- LogP: 4.28
- Rotatable bonds: 8
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.36
- QED: 0.52

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 8.8
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 1.6; units nM; pChEMBL 8.8; comment 849604

## Query Molecule B
- Canonical SMILES: C=CC(=O)Nc1cc2c(Nc3ccc(F)c(Cl)c3)ncnc2cc1OCC1COC2(CCN(C)CC2)C1
- Properties:
- ChEMBL ID: CHEMBL5806859
- Molecular weight: 526.01
- Heavy atoms: 37
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 7
- TPSA: 88.61
- LogP: 5.17
- Rotatable bonds: 7
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.37
- QED: 0.41

## Molecule Similarity
- Weighted Tanimoto: 0.46

Answer: 9