inconsistent results from tautomer calculation

Hi,

when I calculate tautomers, the results are sometimes inconsistent (which is kind of annoying, as we are using the tautomer calculation for the standardization of molecules).

Example:

Fig 1.: Original molecule

Fig 2.: Results of tautomer calculation for original molecule (distribution for pH=7)

Fig 3.: Results of tautomer calculation for tautomer 2 (fig2)

Fig 4.: Results of tautomer calculation for tautomer 3 (fig2)

 

These results are independent from the "protect charge" option. I would expect that the most stable tautomer is always the same...

 

IMHO the problem is that in the generic tautomer the charge is always kept.

 

Greets, Ingo

Hi,

 

I don't want to stress this topic too much, but as you are usually very quick with your answers, I wonder if you may have missed my question.

 

Greets, Ingo

Hi,

 

I'm sorry. There is a "traffic jam"  in my work sometimes. I think I can pay more attention for this problem in the next days.

 

Thanks for reporting this bug.

Jozsi

Hi,

when I calculate tautomers, the results are

sometimes inconsistent (which is kind of annoying, as we are using the

tautomer calculation for the standardization of molecules).

I fixed a certain "shortcoming" in the dominant tautomer generation, and the problem solved now.

 

I think you know that the standardization procedure  invokes the canonical tautomeric form.

On the attached figures I added some example molecules. I want to know your opinion. You can see 3 molecules before and after the standardization. 

My question is:  Do you agree with the standardized molecules?

Thanks.

Jozsi

Hi,

I agree with you that the standardized molecules are the correct solution. In my opinion the dominant tautomer (which should be the one with the highest probability) should always be the same, as long as the query molecules appear in the same tautomerization path.

Can we expect the fix in an upcoming release?

Btw, can you give a short description what the parameter "Protect Charge/aromaticity/..." mean in this context? How do they influence the results?

Greets, Ingo

Hi,

 

Can we expect the fix in an upcoming release?

I think yes. Because of the fix the standardizer and the tautomer generation will be more "clever" than before.  I hope everybody (in-house) will agree with this and the new fix will be available as soon as possible in the next upcoming release.

 

Btw, can you give a short description what the

parameter "Protect Charge/aromaticity/..." mean in this context? How do

they influence the results?

I have attached two figures.  You can study the effect of  the "default options" on the generated tautomers.The first figures is created with the "default settings". The second figure is generated without applying the "default settings".

 

Jozsi