Structure searching in CAS Online using STN Express:
An introductory workshop

Structure searching worksheet

1. Type of structure search needed?
   • ___ Exact
   • ___ Family
   • ___ Closed Substructure (CSS)
   • ___ Substructure (SSS) (default)
2. Want rings in answers to be fused to other ring systems, spiro-attached to other ring systems, or isolated from other ring systems?
   • Ring Fusion
   • ___ Isolated/Embedded (default)
   • ___ Isolated
3. What values are desired for nodes?
   • Node Values
   • ___ Atom
   • ___ Shortcut
   • ___ System-defined variable
   • ___ Variable point of attachment
   • ___ G-group
     
     
   • Node Values — Specific vs. Generic
4. Want atoms in structure to be part of a ring or a chain in answers?
   • Node Characteristics
   • ___ Ring (default for atoms in rings)
   • ___ Chain (default for atoms in chains)
   • ___ Ring/chain
5. What values desired in structure?
   • Bond Values
   • ___ Single
   • ___ Single/Normalized
   • ___ Double
   • ___ Double/Normalized
   • ___ Triple
   • ___ Stereo
   • ___ Unspecified
6. Want bonds in structure to be part of a ring or a chain in answers?
   • Bond Characteristics
   • ___ Ring (default for bonds in rings)
   • ___ Chain (default for bonds in chains)
   • ___ Ring/chain
7. Want to block substitution at a position(s)?
   • ___ Draw in hydrogen atoms
   • ___ Do Exact or Family search
8. Want to force substitution at a position(s)?
   • ___ Use system-defined variable groups
   • ___ Do CSS or SSS search
9. Want to define substitution at a position(s)?
   • ___ Use G-groups
   • ___ Do SSS search