Structures in solid state and solution of dimethoxy curcuminoids: regioselective bromination and chlorination

Structures in solid state and solution of dimethoxy curcuminoids: regioselective bromination and chlorination

BMC Chemistry, June 2013

23800041

Petra Galer, Amalija Golobič, Jože Koller, Berta Košmrlj, Boris Šket

Several papers described the structure of curcumin and some other derivatives in solid and in solution. In the crystal structure of curcumin, the enol H atom is located symmetrically between both oxygen atoms of the enolone fragment with an O···O distance of 2.455 Å, which is characteristic for symmetrical H-bonds. In the solution, the geometry of the enolone fragment is attributed to the inherent disorder of the local environment, which solvates one of the basic sites better than the other, stabilizing one tautomer over the other. In this paper, how the position of methoxy groups in dimethoxy curcuminoids influence the conformation of molecules and how the halogen atoms change it when they are bonded at α-position in keto-enol part of molecules is described.