安装pubchempy
Pypi

pip install pubchempy

或conda

conda install -c mcs07 pubchempy

或本地安装，下载源码

tar -xzvf PubChemPy-1.0.4.tar.gz
cd PubChemPy-1.0.4
python setup.py install

import pubchempy as pcp
import re

def get_substructure_cas(smiles):
    """
    Get CAS number of smiles
    """
    cas_rns = []
    results = pcp.get_synonyms(smiles, 'smiles', searchtype='substructure')
    for result in results:
        for syn in result.get('Synonym', []):
            match = re.match('(\d{2,7}-\d\d-\d)', syn)
            if match:
                cas_rns.append(match.group(1))
    return cas_rns

测试

smiles = 'B1(OC2CC3CC(C3(C)C)C2(O1)C)C(CCC(CC(=O)OC(C)(C)C)O[Si](C)(C)C(C)(C)C)Cl'
get_substructure_cas(smiles)
['1681053-96-2']