Databases for Chemists and Chemical Engineers

Chemical Abstracts

What you draw is what you get …
If you want	Do this
Block ring fusion	Highlight one node in the ring Go to Query Definition in menu bar Click on Ring Isolation Select Isolated
Atoms drawn in a chain to also be part of a ring Atoms drawn in a ring to also be part of a chain	Highight the atom(s) Go to Query Definition in menu bar Click on Node Characteristics Select Ring/Chain
Bonds drawn in a chain to also be part of a ring Bonds drawn in a ring to also be part of a chain	Highight the atom(s) Go to Query Definition in menu bar Click on Bond Characteristics Select Ring/Chain
Bonds with any value	Highlight the bond(s) Go to Draw in menu bar Select Unspecified
Bonds to be either present or absent	Leave bond(s) out of structure Add node characteristics of ring/chain Go to Query Definition in menu bar Click on Node Characteristics Select Ring/Chain
Block substitution at all positions in your structure	Run an Exact or Family structure search if non-carbon atoms are elements or shortcuts and a CSS search if non-carbon atoms include system-defined variables
Block substitution at some positions in your structure	Add hydrogens at appropriate positions
Force substitution at a position in your structure	Go to Draw in menu bar To use system-defined variables, choose Variables To create user-defined variables, choose G-groups