Structural and conformational studies on 5-[1'-methylpyrrolidin-2'-yl]-1,3-oxazolidin-2-one free base and hydrochloride form

The mol. structures of (5R,2'S)-5-[1'-methylpyrrolidin-2'-yl]-1,3-oxazolidin-2-one free base (1) and its enantiomeric hydrochloride salt (2) have been detd. in order to understand their interaction at neuronal acetylcholine receptor. The mols. are in a bent conformation with the pyrrolidine and the oxazolidinone rings nearly at 60° to each other. The mol. assembly is characterized by the formation of chains joined via hydrogen bonds N-H...N in 1 and N-H...Cl in 2. The solid state structures have been compared with the theor. conformations and docked into the crystal structure of Acetylcholine Binding Protein (AChBP), homolog of the ligand binding domain of nAChR. A closer analogy between the receptor bound conformation and the solid state has been found in the hydrochoride form with respect to the free base. This latter (1) forms an hydrogen bond with Trp 6702, while 2 beside two addnl. interactions with Trp 6702 is linked also to Ile 118.