Rapid assembly of the polyhydroxylated b-amino acid constituents of microsclerodermins C, D et E.

A very short and efficient synthesis of protected derivatives of APTO and AETD, the complex polyhydroxylated -amino acid residues present in microsclerodermins C, D, and E, is described. The targets are obtained in only five steps, in 23% and 16% overall yields, respectively. The key transformation involves the completely diastereoselective two-carbon homologation of appropriately selected intermediate chiral sulfinimine

Synthesis, crystal structure, spectral properties and catalytic activityof hexakis(imidazole)manganese(II) bisindole-2-carboxylatobisneocuproine bisdimethyl sulfoxide solvates{[MnII(Im)6].2(2-IC).2(NC).2(DMSO)}

International audienceSynthesis, X-ray crystal structure and IR spectrum of {[MnII(Im)6] Æ 2(2-IC) Æ 2(NC) Æ 2(DMSO)} (Im = imidazole, 2-HIC = indole-2- carboxylic acid, NC = 2,9-dimethyl-1,10-phenanthroline, DMSO = dimethyl sulfoxide) are reported. The manganese(II) ion has octahedral geometry with a MnN6 core. The crystal structure is completed by two NC, two 2-IC- and two DMSO solvate molecules. The individual cations are linked into chains running parallel to the a axis by four intermolecular hydrogen bonding involving two 2-IC-solvate. Moreover, these chains are connected by p–p stacking interactions which occur between neocuproine molecules related through inversion center. In IR spectroscopy, the compound spectrum is roughly similar to the imidazole one: (i) above 1800 cm1, the bands are broad, but when focussing on some of them a doublet structure can be found; (ii) below 1800 cm1, the bands are sharp and it is then possible to point out the modification of S–O band when this later is involved in bifurcated hydrogen bonding to a second solvate 2-IC-. The compound catalyses the disproportionation of H2O2; moreover an additional quantity of imidazole increases the reaction rate

Synthesis, crystal structure ans IR spectroscopy of MnII(2-IC)2(NC)(DMSO) and [M,II(2-IC)2(phen)(H2O)].DMA ; (2-HIC,indole-2-carboxylic acid; phen, 1,10-phenanthroline; NC, 2,9-dimethyl-1, 10-phenanthroline; DMSO, dimethyl sulfoxide; DMA, dimethylacetamide;catalysts for the disproportion of hydrogenperoxide.

International audienceTwo ternary complexes of manganese(II) indole-2-carboxylate (2-IC) with 2,9-dimethyl-1,10-phenanthroline (NC) and 1,10- phenanthroline (phen) in dimethyl sulfoxide (DMSO) or dimethylacetamide (DMA) were synthesized, their X-ray crystal structure and IR spectroscopy characteristics were determined. In compound MnII(2-IC)2(NC)(DMSO) (1), Mn(II) is six-coordinate by one bidentate NC ligand and two bidentate 2-IC anionic ligands. The crystal structure has revealed a seven-coordinate Mn(II) when a moderately long contact distance Mn/O (DMSO 2.643(2) A ° ) is included in the coordination list: the Mn(II) configuration can be described as a distorted capped octahedron. Individual molecules are linked into chains running parallel to the a axis by intermolecular hydrogen bonding. In compound MnII(2-IC)2(phen)(H2O)]/DMA (2), the manganese atom is six-coordinate by one bidentate phen ligand and two 2-IC anionic ligands one of which is monodentate, and the other is bidentate. The coordination sphere is completed by one water molecule, the Mn(II) environment can be described as a very distorted octahedron. The individual molecules are associated in dimmer structure by intermolecular hydrogen bonding. The crystal structure of 2 is completed by a disordered DMA solvate molecule. These two complexes are catalysts for the disproportionation of H2O2 in the presence of added imidazole

Crystal structure of 3,4-dihydroxy-1,5-dimethyl-2-phenylpyrazolium chloride, [C11H13N2O2]Cl

International audienc

Oxidation of arylamidoximes by hydrogen peroxide and horseradish peroxidase in water: Easy preparation and X-ray structure of O-(arylimidoyl)arylamidoximes.

International audienceThe oxidation of arylamidoximes X-C6H4C(NH2)=N-OH (X = H, Me, Cl, NO2, MeO) by H2O2 in the presence of horseradish peroxidase under mild conditions (phosphate buffer pH 7.4, room temperature) yields the corresponding O-(arylimidoyl)arylamidoximes in 30-70% yields. The structure of one of them is established by an X-ray analysis. Copyright (C) 1996 Elsevier Science LtdThe oxidation of arylamidoximes X-C6H4C(NH2)=N-OH (X = H, Me, Cl, NO2, MeO) by H2O2 in the presence of horseradish peroxidase under mild conditions (phosphate buffer pH 7.4, room temperature) yields the corresponding O-(arylimidoyl)arylamidoximes in 30-70% yields. The structure of one of them is established by an X-ray analysis. Copyright (C) 1996 Elsevier Science Lt

Oxidation of arylamidoximes by hydrogen peroxide and horseradish peroxidase in water: Easy preparation and X-ray structure of O-(arylimidoyl)arylamidoximes.

International audienceThe oxidation of arylamidoximes X-C6H4C(NH2)=N-OH (X = H, Me, Cl, NO2, MeO) by H2O2 in the presence of horseradish peroxidase under mild conditions (phosphate buffer pH 7.4, room temperature) yields the corresponding O-(arylimidoyl)arylamidoximes in 30-70% yields. The structure of one of them is established by an X-ray analysis. Copyright (C) 1996 Elsevier Science LtdThe oxidation of arylamidoximes X-C6H4C(NH2)=N-OH (X = H, Me, Cl, NO2, MeO) by H2O2 in the presence of horseradish peroxidase under mild conditions (phosphate buffer pH 7.4, room temperature) yields the corresponding O-(arylimidoyl)arylamidoximes in 30-70% yields. The structure of one of them is established by an X-ray analysis. Copyright (C) 1996 Elsevier Science Lt

Rapid assembly of the polyhydroxylated b-amino acid constituents of microsclerodermins C, D et E.

A very short and efficient synthesis of protected derivatives of APTO and AETD, the complex polyhydroxylated -amino acid residues present in microsclerodermins C, D, and E, is described. The targets are obtained in only five steps, in 23% and 16% overall yields, respectively. The key transformation involves the completely diastereoselective two-carbon homologation of appropriately selected intermediate chiral sulfinimine

Synthesis, crystal structure, IR and Raman properties of 1,2-diacetamidocyclohexane and its complexes with ZnBr2 and HBr3

International audienceX-ray crystallography, infrared absorption and Raman scattering were applied to study the influence of Zn(II) or H+ on the amidic bond. (R,R)-1,2-diacetamidocyclohexane (DAACH) was chosen as a conformationally strained chiral building block including two amide bonds; this model is hoped to be not too far from a peptide and gives easily crystalline complexes. Crystallographic structures of DAACH molecule (1), DAACH/ZnBr2 (2) and DAACH/HBr3 (3) complexes were studied. Complexation of Zn by DAACH is due to the hyperpolarization of the amidic bond. IR and Raman studies of 1-3 agree with the X-ray results. This could be a model in the study of metal/proteins interactions or acidic denaturation of polypeptide

Composés du Pt(II) à visée antitumorale, dérivés de l’ellipticine et de ses analogues

L’environnement du platine dans des composés du Pt(II) à visée antitumorale dérivés de l’ellipticine et de ses analogues, est étudié par spectroscopie d’absorption X. Il est montré que, suivant les conditions de synthèse, on peut obtenir soit des sels de l’anion [PtCl4]2-, soit des composés de coordination dans lesquels le platine est entouré par deux atomes de chlore