Nadir Demirel

Synthesis of R-(-)-2-ethyl-N-benzyl (benzo-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 P21 with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Å, β = 105.51(1)°, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are twomolecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na–-Oeth (etheric) distances are 2.364(6), 2.317(7) Å and the Na–N distances are 2.679(6), 2.611(7) Å; the Na–-O(ClO4) contacts are2.497(7) and 2.257(10) Å, for A and B, respectively.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(-)-1-phenyl-ethyl ammonium percholorate

Abstract A new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group P21 with cell dimensions a = 10.0000(8), b = 12.281(2), c = 12.331(1)Å, β = 102.052(7), Z = 2 The host-guest complex is held together by a strong system of hydrogen bonds between the two protons of the ammonium ion as well as the nitrogen and four oxygen atoms of the crown ether The C—O and C—C distances of the 15-membered ring average 1.418 and 1.501 Å while the O—C—C and C—O—C angles average 110.2 and 113.3°. The average N—C distance is 1.476 Å.

Solvent-free synthesis of chiral Schiff-base ligands based on ferrocene under microwave irradiation and application to enantioselective nitroaldol (Henry) reaction.

Chiral Schiff-bases 3a-f based on ferrocene were designed and synthesized using solvent-free methods by mixing ferrocene carbaldehyde 1 with amino alcohols and amines 2a-f under microwave irradiation and classical method for the enantioselective nitroaldol (Henry) reaction. The Schiff-bases were obtained in shorter reaction times and improved yield under microwave irradiation method over classical method. The highest enantioselectivity was observed in ligand 3e (95% ee) when CH(2)Cl(2) was used as solvent.