Missing error for incorrect stereo-bonds arrangements

[ljubica-milovic]

Steps to Reproduce

1. Go to Ketcher micromolecules mode

2. Draw the following structures:
   

3. Select check structure

Actual behavior

Ketcher doesn't display a warning about incorrect stereo-bonds arrangement.

Expected behavior

In non-cyclical structures opposite bonds (up and down) can be drawn next to each other, and the same bonds (two up or two down) can be drawn opposite to each other.

If the same bonds are drawn next to each other, or two opposite bonds are drawn opposite each other, that should lead to a stereochemistry warning message, if those stereo-bonds are not a part of a ring.

The error message should be under stereochemistry warning: Structure contains incorrect stereochemistry.

Closely related issue #4810

Ketcher version v2.21.0

[iRadionova]

Please, clarify the steps to reproduce:

[ljubica-milovic]

Hi @iRadionova!

Looks like some of the older tickets have lost their images.

For a chiral carbon (or any other chiral center with 4 bonds) that is not part of the circular structure, the only acceptable arrangement of stereo bonds is:

• One up and one down, next to each other:
  
• Two up or two down, opposite each other:
  

Any other arrangement, for example this:

should, ideally, result in a warning to the user.