Improvements to version 4.61:
SMIRKS added/deleted parts:
Created/eliminated atoms can be combined in a single SMIRKS:
Atom-mapped nodes must still be mapped pairwise, with no
This is most appropriate for reagants and unimportant leaving groups,
not appropriate for variable groups as part of the reaction.
[Pb]>>[Au] is a legal transformation (there aren't any atoms mapped
in this example - it's a complete replacement).