from frowns import Smiles m = Smiles.smilin("N[C@](C)(F)C(=O)O") print "initial smiles:", m.arbsmiles(isomeric=1) print "canonical smiles:", m.cansmiles(isomeric=1) print m = Smiles.smilin("[C@H](C)(F)(O)") print "initial smiles:", m.arbsmiles(isomeric=1) print "canonical smiles:", m.cansmiles(isomeric=1)