Structure and activity studies of glycine receptor ligands, Part 3: structure and conformation of ethyl-N-[(5,5-diphenyl)-4-oxo-2-imidazolidyl]glycinate

Abstract As part of our investigation of compounds with potential affinity to the glycine binding site of MNDA receptors the structure of ethyl-N-[(5,5-diphenyl)-4-oxo-2-imidazolidyl]glycinate is reported: C 19 H 19 N 3 O 3 ; orthorombic; P2 1 2 1 2 1 ; a = 10.273(2), b = 10.309(2), c = 16.721(3) A ; V = 1770.8(6) A 3 ; Z = 4; λ( CuK α) = 1.54178 A ; μ = 0.71 mm −1 ; final R = 0.053 for 1002 observed reflections [ I > 4 σ ( I )]. Possible tautomers of this structure as well as possible conformations of the amino ester chain and their impact on the binding to the glycine binding site of MNDA receptors are discussed.