SMILES :)

SMILES is "Simplified Molecular Input Line Entry System". Used to translate a chemical's 3D structure into symbols that can easily understood by computer software.

Software that used SMILES notation :
1) EPI Suite
2) ECOSAR

There are some differences in writing SMILES bonds :
1) - for single bond also can be omitted
2) = for double bond
3) # for triple bond
4) : for aromatic bond also can be omitted

SMILES atoms

• aliphatic or non-aromatic carbon is denoted as C (upper case)
• atomm inn aromatic ring is denoted as c (lower case)
• Designaate ring closure with pairs of matching digits, for example :

c1ccccc1 (or C1=CC=CC=C1) is Benzene

C1CCCCC1 is Cyclohexane

For charges in SMILES, it must be written in a []. Examples of SMILES CHARGERS:

[H+]

[O-]

There are some rules to write the Cyclic Structures formula in SMILES.

• same numbers indicate start and stop of a ring
• only numbers 1 to 9 are used
• same number should appear only twice
• an atom can be associated with 2 consecutive numbers in some cases

Further restrictions in SMILES notation:

•  a branch cannot begin a SMILES notation
• a branch cannot immadiately follow a double- or triple-bond symbol

There is an easy way to practice this SMILES notation. :) We can download the ChemSketch software and install it at this link http://chemsketch.soft32.com/free-download/ . Have a nice try !😁