Tetrahedral centers of symmetric molecules

Hy all,

we notice some problems in the definition of the absolute stereochemistry of tetrahedral centers, when the molecule is symmetric.

As you see in the attached picture "comparision" the stereochemistry-label of the carbon-atom next to the oxygen changes from (R) to (S) when the molecule is mirrored. This is absolutely correct, when there is no symmetry in the molecule, but in this case we have a symmetry and so the mirrored molecule has exactly the same topology as the original one.

 Maybe there is an error in the definition of tetrahedral centers (see attached picture "tetrahedral centers")

Thanks for your comments.

Udo

Hi,

It seems this is a bug, we will fix it soon.

Thanks for the report.

János

Maybe a related problem is the displayed stereo-information in the attached example "9-azabicyclo[3.3.1]nonan-3-amine". I tried to draw the two possible stereoisomers in Marvin-Sketch.

When I draw the octyl-ring flat, the amino-bridge up and the NH2-group down it should be exactly the same molecule as the amino-bridge down and the NH2-group up (see attached picture).

In MarvinSketch 6.1.2 the stereocenters of these two identical compounds are marked differently.

This also seems to be a bug.

Regards
Udo

 

Hi,

It seems ti will be the same bug. Thanks the examples.

Janos