In case you want to remove the data fields from the structures stored in sdf format, the following UPDATE statement can be helpful:
UPDATE <table> SET <structure_column> = substring(<structure_column>::text,'^.*M\ \ END')::molecule('molecule_subtype');
UPDATE mytable SET mol = substring(mol::text,'^.*M\ \ END')::molecule('sample');
The following business rules can be defined in the molecule type files.
If you want more than one combination of the above listed business rule parameters be available - for example you want to run searches with and without tautomer search - you have to create separate table columns with different molecule types. Unfortunately, this means duplication, multiplication of the stored chemical structure data.
In the case molecule types with tautomer=GENERIC parameter, similarity search gives false results. These is no workaround at the moment, please do not execute similarity search in structure columns having molecule type with tautomer=GENERIC parameter.