Abstract
Simplified Molecular-Input Line-Entry System or SMILES is a notation
scheme for representing chemical structures in a single line of text,
encoding atom connectivity and stereochemistry, as well as charge and
ring structures. There are a large number of possible SMILES notations
for any one chemical structure, which has led to the development of the
canonical SMILES notation. In contrast, I describe here a SMILES
approach or “perspective” which encodes functional groups into valid
SMILES strings. It is shown that this functional SMILES perspective
further simplifies the human interpretation of SMILES strings, can be
easily formed from reading IUPAC nomenclature, and has the ability to
encode limited chemical reaction histories.