## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: Ki
- Label type: continuous
- Binary semantics: pchembl
- Assay description: δ-Opioid Receptor Binding Assay: δ-Opioid Receptor Binding Assay Procedures: δ-Opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33 Ci/mmole) with 5 μg membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 μl binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates are counted in a Packard Top-Count for 1 min/well.δ-Opioid Receptor Binding Data: In certain embodiments, Compounds of the Invention exhibit a Ki (nM) for δ receptors of about 10,000 or more (which, for the purposes of this invention, is interpreted as having no binding to the δ receptors). Certain Compounds of the Invention exhibit a Ki (nM) of about 20,000 or less for δ receptors. In one embodiment, Compounds of the Invention exhibit a Ki (nM) of about 10,000 or less; or of about 9000 or less for δ receptors. In another embodiment, Compounds of the Invention exhibit a Ki (nM) of about 7500 or less; or of about 6500 or less; or of about 5000 or less; or of about 3000 or less; or of about 2500 or less for δ receptors. In another embodiment, Compounds of the Invention exhibit a Ki (nM) of about 1000 or less; or of about 500 or less; or of about 350 or less; or of about 250 or less; or of about 100 or less; or of about 10 or less for δ receptors.
- Assay organism: Homo sapiens
- Target name: Delta-type opioid receptor
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: O=C(O)[C@@H]1C[C@]23CCN(CC4CC4)[C@H](Cc4ccc(O)cc42)[C@]3(O)C1
- Properties:
- ChEMBL ID: CHEMBL5918633
- Molecular weight: 343.42
- Heavy atoms: 25
- Hydrogen bond donors: 3
- Hydrogen bond acceptors: 4
- TPSA: 81
- LogP: 1.9
- Rotatable bonds: 3
- Ring count: 5
- Aromatic rings: 1
- Formal charge: 0
- Fraction Csp3: 0.65
- QED: 0.78

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 7.25
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type Ki; relation =; value 55.6; units nM; pChEMBL 7.25; comment 593089

## Query Molecule B
- Canonical SMILES: COc1ccc2c(c1)[C@]13CCN(CC4CC4)[C@H](C2)[C@]1(O)C[C@H](C(N)=O)C3
- Properties:
- ChEMBL ID: CHEMBL5867402
- Molecular weight: 356.47
- Heavy atoms: 26
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 4
- TPSA: 75.79
- LogP: 1.6
- Rotatable bonds: 4
- Ring count: 5
- Aromatic rings: 1
- Formal charge: 0
- Fraction Csp3: 0.67
- QED: 0.86

## Molecule Similarity
- Weighted Tanimoto: 0.62

Answer: 5.53