AddH inverts chral centers??

I've seen this before, but the attached .mol file is a good example: it contains a heavy-atom sketch with up/down wedges specifying the chirality of the center, although the fourth substituent on the chiral center, a H, is at this time missing. If you do Viev->Misc->R/S labels->All, it will display (R) or (S) just fine, in assuming that the H is oppositely arranged wrt. the wedged substituent (err... I SUPPOSE that those labesl are correct - too lazy to check Cahn-Ingold-Prelog rules all by myself, gives me the headache!) Now, if you go to Edit->AddH, some H atoms are thown in... and some R/S labels change!! One may select and move a H atom in the sketch plane... and thus manually reinvert the chirality, as if Marvin'd use the 2D-protogeometry to decide for chirality, and ignores wedges - probabily because the H were NOT added with a wedge, but with a simple bond. I suppose there might be a theoretical workaround: persuade chemists to always specify BOTH up & down wedges when drawing... but this has as many chances of success as W's plan of bringin' democracy to Irak. Other ideas?





Cheers,


Dragos

Hi,





It was a bug in the earlier marvin versions. But it has been already fixed (Jul 2004).


I have checked marvin 3.4 and it worked fine.


Which marvin version are you using?





All the best


Andras