Retrosynthesis Validation

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Structures submitted for retrosynthesis are validated for errors or unsupported features.

Retrosynthesis Not Available

If you receive the "Retrosynthesis is not available for this structure" message, the target structure has at least one of the following:

  • Multiple fragments with none of them or more than one assigned a product role.
  • Variability in the structure, defined as:
    • Variables.
    • R-groups.
    • Repeating groups (with a range); a fixed repeating group range like 4-4 is NOT variable.
    • Variable Attachment Points (VAPs).
    • Unspecified bonds.
  • Less than 5 connected non-hydrogen atoms.
  • Double wedge bond.
  • Hydrogen isotopes (deuterium, tritium).
  • More than 15 rings.

    _SFn-Retro-NotAvailableForStructureMessage.png

Unsupported Features Removed

If the structure contains more than one fragment and only one fragment has a product role then:

  • All fragments with a non-product role are removed from the structure.
  • Any reaction roles or sites are removed from the structure.

If the structure is a single fragment with no variability, any reaction role or reaction sites are removed from the structure. Variability is defined as the structure/fragment possessing:

  • Variables
  • R-Groups
  • Repeating Groups (with a range; a fixed repeating group range like 4-4 is NOT variable)
  • Variable Attachment Points (VAPs)
  • Unspecified bonds