rdkit/rdkit — pull request #211 by TobyWright (2014-01-29 11:52:23+00:00)
Title: Added a stricter definition of rotatable bonds as a new function in the ...

Added a stricter definition of rotatable bonds as a new function in the CPP, Python, Java and DB cartridges, called calcNumStrictRotatableBonds or similar (eg numstrictrotatablebonds in the DB cartridge). Essentially everywhere you could ask for a count of rotatable bonds you can now ask for the strict version if you would rather.

Under Strict rules a bond is rotatable iff it is a single non-ring bond where neither atom is terminal or in a terminal group or where a conjugated system involving amides, esters, sulfonamides etc appear. A terminal group is defined as any of the following: C(F)(F)F, C(Cl)(Cl)Cl, C(Br)(Br)Br or C([CH3])([CH3])[CH3]