Python script to convert SMILES notation to IUPAC names

Converting SMILES notation to IUPAC names involves the use of a library that can perform chemical nomenclature. The openbabel library is a versatile tool for this purpose. Before using it, you need to install the library. You can do this using:

pip install openbabel

Here’s a Python script that uses openbabel to convert SMILES notation to IUPAC names:

from openbabel import openbabel

def smiles_to_iupac(smiles):
    # Initialize the OpenBabel molecule
    obConversion = openbabel.OBConversion()
    obMol = openbabel.OBMol()
    
    # Convert SMILES to OpenBabel molecule
    obConversion.SetInFormat("smi")
    obConversion.ReadString(obMol, smiles)

    # Generate IUPAC name
    iupac_name = obConversion.GetIUPACName(obMol)

    return iupac_name

if __name__ == "__main__":
    # Example usage
    smiles_notation = "CCO"
    iupac_name = smiles_to_iupac(smiles_notation)
    print(f"IUPAC Name for {smiles_notation}: {iupac_name}")

In this script:

1. We use the openbabel library to initialize an OpenBabel molecule (obMol).
2. The smiles_to_iupac function takes a SMILES string as input, converts it to an OpenBabel molecule, and retrieves the IUPAC name.
3. Example usage is provided for a SMILES string (“CCO”).

Make sure to replace the smiles_notation variable with your desired SMILES string.

Note: While openbabel is a powerful tool for chemical conversion, the accuracy of IUPAC names depends on the complexity of the molecule and the rules of nomenclature. It may not always provide human-readable names for highly complex structures.