How to read or write the properties block of molfiles using RDKit?

[lucas-morin]

Hello,
Do you know if RDKit allows to read or write the property block of molfiles?

For example, in the following molfile, I would like to read the abbreviation "OCH3" directly from the S-group definition.

from rdkit import Chem

molecule = Chem.MolFromMolBlock("""0121.cdx
  ChemDraw04300520492D

 12 13  0  0  0  0  0  0  0  0999 V2000
   -0.9920    0.7219    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   -0.9920   -0.1031    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   -0.2775   -0.5156    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
    0.4369   -0.1031    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
    0.4369    0.7219    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   -0.2775    1.1344    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   -1.7065   -0.5156    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
    1.2216   -0.3581    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
    1.7065    0.3094    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
    1.2216    0.9768    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
   -0.6348   -0.7219    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
    0.0797   -1.1344    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  4  0      
  2  3  4  0      
  3  4  4  0      
  4  5  4  0      
  5  6  4  0      
  6  1  4  0      
  2  7  1  0      
  4  8  1  0      
  8  9  1  0      
  9 10  1  0      
 10  5  1  0      
  3 11  1  0      
 11 12  1  0      
M  STY  1   1 SUP
M  SLB  1   1   1
M  SAL   1  2  11  12
M  SBL   1  1  12
M  SMT   1 OCH3
M  SBV   1 12   -2.4599    6.1489
M  END""")

Here is the extracted structure:

Ideally, the atoms corresponding to "OCH3" would be merged to a single node, having a display label "OCH3", like in the following structure:

Conversely, I would like to change the display label of a node and preserve this information when saving the molecule.

from rdkit import Chem
molecule = Chem.MolFromSmiles("CCCCC")
molecule.GetAtomWithIdx(0).SetProp("_displayLabel", "test") 
rdmolfiles.MolToMolFile(molecule, "test.mol")

Are these features supported in RDKit?

[greglandrum]

@lucasmorin222, the rdkit.Chem.rdAbbreviations module has code for working with abbreviations.
There's info on this in the cookbook: https://www.rdkit.org/docs/Cookbook.html#with-abbreviations
And here is a demo with your molecule:
https://gist.github.com/greglandrum/f86587a196da572a2f8b813e429c19e7

[lucas-morin]

Thanks a lot, this is what I was looking for.