Synthesis of R-(-)-2-ethyl-N-benzyl (monoaza-15-crown-5) and the crystal structure of its sodium perchlorate complex

A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P2(1) with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Angstrom, beta = 105.51(1)degrees, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are two molecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na-O-eth (etheric) distances are 2.364(6), 2.317(7) Angstrom and the Na-N distances are 2.679(6), 2.611(7) Angstrom; the Na-O(ClO4) contacts are 2.497(7) and 2.257(10) Angstrom, for A and B, respectively.