incorrect aromaticity in converting to daylight smiles

User 52167fe300

24-03-2006 18:53:57

I am trying to convert cmpds to daylight aromatized smiles format (e.g. smiles:a_day-H). But somehow this cmpd is not aromatized according to daylight definition of aromaticity. The atoms in the 7-member ring should not be aromatic. Any explanation for this. Is this a bug in the conversion? Thanks,








S=C1NN=CC2=NNC3=NN=NC1=C23

ChemAxon 25dcd765a3

26-03-2006 14:36:33

Hi





Every ring is aromatic in the specified SMILES (S=C1NN=CC2=NNC3=NN=NC1=C23) according to Daylight definition of aromaticity.


I also faced this problem at the time I wrote the aromatization. The reason is the following:


Take the whole ring system. It has 14 electrons altogether:


5 double bonds give 10 electrons, the two N gives 4 electrons, and no other atom gives any more electron.


The 14 electrons satisfy the Huckel rule (4N+2).





Moreover, the compound is also aromatic according to the Daylight site:


http://www.daylight.com/daycgi_tutorials/cansmi.cgi





All the best


Andras