TautomerCanonicalizer gives unexpected/forbidden form of phosphoric acid about molvs HOT 3 OPEN

NADH looks like this

original_smiles = 'NC(=O)C1=CN([C@@H]2O[C@H](COP(=O)(O)OP(=O)(O)OC[C@H]3O[C@@H](N4C=NC5=C4N=CN=C5N)[C@H](O)[C@@H]3O)[C@@H](O)[C@H]2O)C=CC1'

original_mol = Chem.MolFromSmiles(original_smiles)
tautomerized_mol = TautomerCanonicalizer().canonicalize(original_mol)

Draw.MolsToGridImage([original_mol,tautomerized_mol],
                     molsPerRow=1,subImgSize=(600,300),
                     legends=['original','tautomer'])

from molvs.

I think this is caused by the phosphonic acid rules: https://github.com/mcs07/MolVS/blob/master/molvs/tautomer.py#L130

It can probably be fixed by making the SMARTS pattern more strict to match only the intended target:
https://en.wikipedia.org/wiki/Phosphorous_acid

from molvs.

You are correct, removing that rule stops that moiety from being modified. When you say, "more strict", you think specify an explicit number of bonds on the Phosphorous in the SMARTS pattern?

Why does rdkit allow 7 bonds on the phosphorous? Rdkit is a vast package, but looking at the definition of Phosphorous, it has max bonds of 5.

If I do SantizeMol, the hydrogen stays put. When I paste the structure into ChemDraw, its not valid.

from molvs.