Cyanosilylation of Aldehydes Catalyzed by Iron(III) Arylhydrazone-β-Diketone Complexes

Two known iron(iii) complexes, [Fe(H2O)3(L1)]·xH2O (x≤4 (1), 5 (2)) and [Fe(H2O)3(L2)]·3H2O (3), bearing the basic forms of 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonic acid (H3L1) and 3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonic acid (H3L2), were prepared and used as homogeneous catalysts for cyanosilylation of a variety of aldehydes with trimethylsilyl cyanide leading to the corresponding cyanohydrin trimethylsilyl ethers. High yield (up to 98%) was observed in the reaction catalyzed by 3 at room temperature in methanol. © CSIRO 2018

Trinuclear and polymeric cobalt(II or II/III) complexes with an arylhydrazone of acetoacetanilide and their application in cyanosilylation of aldehydes

The new trinuclear [CoII(H2O)2(Me2NCHO)2{CoIII(1κNOO′:2κO″-μ-HL)}2(1κNOO′)]·2H2O (1) and polymeric [CoII(1κNOO′:2κO″-μ-HL)(MeOH)2]n (2) complexes were isolated by the reaction of (Z)-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazinyl)benzoic acid (H3L) with CoCl2·6H2O and Co(ClO4)2·6H2O, respectively, in a mixture of DMF/MeOH (1/10, v/v), in the presence of Et3N at room temperature, and characterized by IR and ESI-MS spectroscopies, elemental and X-ray crystal structural analyses. In both structures the cobalt centres display distorted octahedral geometries. The structural units in 1 and 2 are connected via intermolecular hydrogen bonds involving the coordinated HL2− and the bound and non-bound water molecules (in 1) or the methanol ligands (in 2) which provides supramolecular networks. 1 and 2 are catalyst precursors for the cyanosilylation reaction of a variety of both aromatic and aliphatic aldehydes with trimethylsilyl cyanide leading to the corresponding cyanohydrin trimethylsilyl ethers in high yields (up to 89%) in methanol and at room temperature. © 2017 Elsevier B.V

Methyl 7,8-diacetoxy-11-oxo-5-(2-oxopyrrolidin-1-yl)-7,9-epoxycyclopenta- [4,5]pyrido[1,2-a]quinoline-10-carboxylate sesquihydrate

The title compound, C26H28N2O 9·1.5H2O, the product of an acid-catalysed Wagner-Meerwein skeletal rearrangement, crystallizes as a sesquihydrate with the O atom of one of the two independent water mol-ecules occupying a special position on a twofold axis. The organic mol-ecule comprises a fused penta-cyclic system containing two five-membered rings (cyclopentane and tetrahydrofuran) and three six-membered rings (piperidinone, tetra-hydropyridine and benzene). The five-membered rings have the usual envelope conformations, and the central six-membered piperidinone and tetra-hydropyridine rings adopt boat and sofa conformations, respectively. In the crystal, there are three independent O-H⋯O hydrogen bonds, which link the organic mol-ecules and water mol-ecules into complex two-tier layers parallel to (001). The layers are further linked into a three-dimensional framework by attractive inter-molecular carbonyl-carbonyl inter-actions

Methyl 4,5-diacetoxy-1-oxo-2-phenylperhydro-4,6-epoxycyclopenta-[c] pyridine-7-carboxylate ethanol solvate

The title compound, the product of an acid-catalysed Wagner-Meerwein skeletal rearrangement, crystallizes as an ethanol monosolvate, C 20H21NO8·C2H6O. The title mol-ecule comprises a fused tricyclic system containing two five-membered rings (cyclo-pentane and tetra-hydro-furan) in the usual envelope conformations and one six-membered ring (piperidinone) adopting a flattened twist-boat conformation

Crystal strucutre of rac-methyl (11aR∗,12S∗,13R∗,15aS∗,15bS∗)-11-oxo-11,11a,12,13-tetrahydro-9H,15bH-13,15a-epoxyisoindolo[1,2-c]pyrrolo[1,2-a][1,4]benzodiazepine-12-carboxylate

The title compound, C21H18N2O4, obtained as a racemate, contains a novel heterocyclic system, viz. isoindolo[1,2-c]pyrrolo[1,2-a][1,4]benzodiazepine. The central diazepane ring has a distorted boat conformation with two phenylene-fused and one methine C atom deviating by 0.931(1), 0.887(1) and 0.561(1)Å, respectively, from the mean plane of the rest of the ring. The γ-lactone ring has an envelope conformation, with the C atom opposite to amide bond deviating by 0.355(1)Å from its plane. In the crystal, molecules form centrosymmetric dimers through pairs of C-H⋯O hydrogen bonds. © 2014

Methyl 7,8-diacetoxy-11-oxo-5-(2-oxopyrrolidin-1-yl)-7,9-epoxycyclopenta- [4,5]pyrido[1,2-a]quinoline-10-carboxylate sesquihydrate

The title compound, C26H28N2O 9·1.5H2O, the product of an acid-catalysed Wagner-Meerwein skeletal rearrangement, crystallizes as a sesquihydrate with the O atom of one of the two independent water mol-ecules occupying a special position on a twofold axis. The organic mol-ecule comprises a fused penta-cyclic system containing two five-membered rings (cyclopentane and tetrahydrofuran) and three six-membered rings (piperidinone, tetra-hydropyridine and benzene). The five-membered rings have the usual envelope conformations, and the central six-membered piperidinone and tetra-hydropyridine rings adopt boat and sofa conformations, respectively. In the crystal, there are three independent O-H⋯O hydrogen bonds, which link the organic mol-ecules and water mol-ecules into complex two-tier layers parallel to (001). The layers are further linked into a three-dimensional framework by attractive inter-molecular carbonyl-carbonyl inter-actions

Chalcogen and Hydrogen Bonds at the Periphery of Arylhydrazone Metal Complexes

Ligands comprising an intramolecular resonance-assisted hydrogen bond (RAHB) and an intramolecular resonance-assisted chalcogen bond (RAChB) have been used to form Cu(II), Ag(I), and Cd(II) metal complexes. Both interactions undergo major changes on ligand binding to the metal even though metal-ligand binding does not directly involve either interactions. In fact, the RAChB synthon can act as an intermolecular H-bond donor or acceptor, is involved in intramolecular coordination-coupled proton transfer, or exhibits an ionic pattern. © 2022 American Chemical Society. All rights reserved

Water-soluble Al(iii), Fe(iii) and Cu(ii) formazanates: synthesis, structure, and applications in alkane and alcohol oxidations

A series of water-soluble metal formazanates, [Al2(OH)2(H2O)8](HL)2 (1), [{Fe(H2O)4}(HL)(H2L)]·2H2O (2) and [Cu(en)2(H2O)2][CuL(H2O)2]2 (3), were synthesized by the reaction of sodium 2-(2-((E)-cyano((E)-(2-sulfonatophenyl)diazenyl)methylene)hydrazineyl) benzenesulfonate (Na2HL) with Al(NO3)3·9H2O, FeCl3·6H2O and Cu(NO3)2·3H2O (in the presence of ethylenediamine) in methanol, respectively. The formazan pro-ligand Na2HL and its complexes 1-3 were characterized by ESI-MS, 1H/13C NMR (for Na2HL), IR spectroscopy, elemental and X-ray diffraction analyses (for 1-3). According to the X-ray analysis, the formazanate behaves as an anion or displays a mono- or bidentate coordination mode, for the Al, Fe or Cu centre, respectively. All complexes were tested as catalysts for the peroxidative (with H2O2) oxidation of cyclohexane and cyclohexanol to the coresponding organic products at room temperature. The complexes 2 and 3 are active homogeneous catalysts for the microwave-assisted peroxidative oxidation with aqueous H2O2 of cyclohexane (to cyclohexanol and cyclohexanone) and cyclohexanol to cyclohexanone. © 2022 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique