The ‘functional group’ is an atom, or a group of atoms that has similar chemical properties whenever it occurs in
different compounds. It defines the characteristic physical and chemical properties of families of organic compounds
(
http://goldbook.iupac.org/F02555.html). The functional groups were obtained using Checkmol, a free and an open source
tool,
checkmol, detect and assign the functional group information on any small molecules with 2D coordinates. The
Checkmol is a command-line utility program, which reads molecular structure files in different formats and analyzes the
input molecule for the presence of various functional groups. Analysis of Functional Groups in Organic Molecules, N. Haider, “Functionality pattern matching as an efficient
complementary structure/reaction search tool: an open-source approach”, Molecules 15 (8) (2010) 5079–5092
(
http://www.mdpi.com/1420-3049/15/8/5079). List of functional groups generated by Checkmol can be viewed
here.