2009/12/15 Noel O'Boyle <[email protected]>:
> 2009/12/15 Noel O'Boyle <[email protected]>:
>> 2009/12/14 Geoffrey Hutchison <[email protected]>:
>>>> So I thought about changing the fragment to be composed of C atoms and
>>>> using that to derive the canonical representation.
>>>
>>> The problem is that if you change the fragment to C atoms, you have lots of 
>>> un-filled valence. Consider, changing the "N" in pyrrole (or S in 
>>> thiophene) to carbon. It's no longer aromatic. So with that approach 
>>> (making fragments, changing atoms to carbon, writing output), the resulting 
>>> SMARTS patterns weren't
>>
>> Got you.
>>
>>> I see your point. Perhaps the "best" solution is to look for similar SMARTS 
>>> in the post-processing step and merge them?
>>
>> Aha, finally a use for canonical SMARTS strings! Which I'm afraid we
>> don't have. But I might be able to identify at least the simpler
>> duplicates.
>
> Actually just thought of a way to create canonical SMARTS string.
> Craig, do you have code for generating all possible SMILES strings for
> a particular molecule? If so, then I could do this for each fragment,
> do string replacement to create the corresponding SMARTS, and pick the
> 'canonical SMARTS' with the lowest alphabetical order.

Sorry - I see that the code is already in OpenBabel with the "C"
option to the SMILES writer.

>>> Craig, do you have another solution? Is there a wild-card or dummy atom for 
>>> the canonical SMILES?
>>>
>>> -Geoff
>>
>

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