Does a resource exist that has the SMILES formula of the generalized pattern that represents the group?
For instance: I have the aldehydes group, which has the pattern: -CHO
. Is there a resource that lists each functional group with the generic pattern that defines the group and its SMILES representation?
I'm hoping for, at the very least, getting the SMILES formula for the functional groups represented in this pdf: EPA Chemical Compatibility Chart
Follow up question: Is SMILES still relevant or are there better ways to represent chemicals?
C=O
$\endgroup$C=O
matches ketones and carboxylates in addition to aldehydes. The trick with functional group specification is in excluding things that shouldn't be matched, rather than forming things which do. This is why SMARTS, rather than SMILES, tends to be better for substructure searching. SMARTS is basically just SMILES with additions which help in querying. $\endgroup$C(=O)
, they don't need to:C1CCCCC1=O
is a perfectly valid SMILES for cyclohexanone. Likewise, while aldehydes often containC=O
, they don't need to:O=CC
is a valid SMILES for acetaldehyde, as isCC(=O)[H]
. Conversely,CCOC=O
(ethyl formate) is not an aldehyde. As such, pretty much any decent substructure search program that takes SMILES does not do text searches, and will give back ketones, esters, etc. for a query ofC=O
. $\endgroup$