Efficient Synthesis of Nicotinic Acid Based Pseudopeptides Bearing an Amidoxime Function

International audienceThe synthesis of nicotinic acid based amino acid units bearing an amidoxime function on the pyridine ring has been developed. The starting 2-cyanonicotinic acid was efficiently coupled with methyl esters of l―amino acids to afford intermediate 2-cyanopyridin-3-yl-containing pseudopeptides together with the tautomeric methyl esters of (2S)-2-(7-imino-5-oxo-5,7-dihydro-6H-pyrrolo[3,4-b]pyridin-6-yl)alkano ic acids. Regioselective pyrrolidine ring opening of these esters occurred upon hydroxylamine hydrochloride treatment, giving rise to the open-chain pyridin-3-yl 2-amidoxime pseudopeptides bearing the same structure as amidoximes obtained by direct hydroxyamination of the corresponding cyano esters

Functionalized organic frameworks explored as second order NLO agents

A new class of chiral phthalimides functionalized with aryl piperazines was designed anticipating their strong candidature for crystal engineering and technological applications. Five new phthalimides were synthesized, characterized and subjected to single crystal X-ray diffraction study that directed their non-centrosymmetric structures. Four phthalimides crystallized in P2(1) space group with monoclinic crystal system, however, one was found to possess P2(1)2(1)2(1) space group with orthorhombic system. The supramolecular architectures of phthalimide crystals were analysed by an approach based on consideration of energy of intermolecular interaction. The molecular hyperpolarizability (beta) calculation for all the listed phthalimides indicated their promising candidature for NLO materials. Further, the crystalline form of all phthalimides was evaluated for their second harmonic generation (SHG) response. A significant response of 16.4 mV was measured for phthalimide possessing t-butyl substituent at the para position of 4-benzylpiperazine. This high SHG response may be attributed to the molecular chirality and helical supramolecular frameworks stabilized by C-H center dot center dot center dot O hydrogen bonds in the solid state. The current study attests chiral phthalimides possessing arylpiperazines as effective nominees to the area of crystal engineering and nonlinear optics

Tris[dimethyl (benzoylamido)phosphato-κ2O,O′](1,10-phenanthroline-κ2N,N′)neodymium(III)

In both independent molecules of the title compound, [Nd(C9H11NO4P)3(C12H8N2)], the NdIII atom is coordinated by six O atoms belonging to three phosphoryl ligands and two N atoms of 1,10-phenanthroline in a dodecahedral geometry. In the phosphoryl ligands, the benzene rings are twisted with respect to the planes of the sp2-hybridized C atoms of the chelate rings by 12.1 (1)–24.7 (1)°