Search results for "Halogen"

ChemInform Abstract: Electroorganic Synthesis of Nitriles via a Halogen-Free Domino Oxidation-Reduction Sequence.

2016

A direct electroorganic sequence yielding nitriles from oximes in undivided cells is reported. Despite the fact that intermediate nitrile oxides might be formed, the method is viable to prepare benzonitriles without substituents ortho to the aldoxime moiety. This constant current method is easy to perform for a broad scope of substrates and employs common electrodes, such as graphite and lead.

ChemInform Abstract: Elemental Bromine Production by TiO2Photocatalysis and/or Ozonation.

2016

Significant production of elemental bromine (Br2 ) was observed for the first time when treating bromide containing solutions at acidic pH, with TiO2 photocatalyst, ozone, or a combination thereof. Br2 selectivities up to approximately 85 % were obtained and the corresponding bromine mass balance values satisfied. The process is general and may be applied at a laboratory scale for green bromination reactions, or industrially as a cheap, safe, and environmentally sustainable alternative to the currently applied bromine production methods.

ChemInform Abstract: Acid-Mediated Reaction of Bis(pyridine)iodonium(I) Tetrafluoroborate with Aromatic Compounds. A Selective and General Iodination…

2010

Reaction of aromatic compounds with bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4) in the presence of HBF4 or CF3SO3H in CH2Cl2 at room temperature furnishes monoiodo derivatives with excellent regioselectivity and yields. Use of either acid gives comparable results with activated aromatics, whereas CF3SO3H is much more effective in the iodination of deactivated aromatics. © 1993 American Chemical Society.

Oxidative halogenation of substituted pyrroles with cu(II). Part I. Bromination of some 3-acetylpyrroles

1990

3-Acetylpyrroles are brominated with copper(II) bromide. The reaction afforded almost quantitatively only nuclear monobromination. Evidence for the structures of final compounds was by mass spectrometry, 1 H-nuclear magnetic resonance, ir, and elemental analysis

Oxidative halogenation of substituted pyrroles with cu(II). Part II. Bromination of some ethyl 3-pyrrolecarboxylates and corresponding acids

1990

Ethyl 3-pyrrolecarboxylates and their corresponding acids are brominated with copper(II) bromide. The reaction afforded at 0°, with high-yield nuclear monobromination.

Preparation, reactivity and tautomeric preferences of novel (1H-quinolin-2-ylidene)propan-2-ones

2006

1,1-Difluoro-3-(1H-quinolin-2-ylidene)propan-2-one 1a, 1,1,1-trifluoro-3-(1H-quinolin-2-ylidene)propan-2-one 1b, 1,1,1-trifluoro-3-(4-chloro-1H-quinolin-2-ylidene)propan-2-one 1c and 1,3-dibromo-1,1-difluoro-3-(2-quinolyl)propan-2-one 2 are prepared and characterized by various spectroscopic techniques. The crystal structure of 1a is determined by X-ray diffraction. Furthermore, a series of previously known non-halogenated (1H-quinolin-2-ylidene)propan-2-ones 1d-1h are oxidized with AgBrO3 in the presence of AlCl3. In all cases, 2-(1-bromo-1-chloromethyl)quinoline 3 is obtained in high yield. The bromination order and sites of 1a are analyzed based on ab initio MP2 and DFT calculations for …

HALOGEN AS A READILY CLEAVABLE PROTECTIVE GROUP FOR REACTIVE POSITIONS IN PHENOLS AND PHENOLIC COMPOUNDS

1976

(3RS,1SR)-3-Bromo-3-(1-phenylpropyl)chroman-2,4-dione

2005

The title compound, C18H15BrO3, was obtained by bromination of phenprocoumone with N-bromo­succin­imide. The X-ray structure confirms an earlier proposal concerning the regioselectivity of the reaction to introduce the Br atom at the 3-position.

Halogen bond preferences of thiocyanate ligand coordinated to Ru(II) via sulphur atom

2017

Halogen bonding between [Ru(bpy)(CO)2(S-SCN)2] (bpy = 2,2’-bipyridine), I2 was studied by co-crystallising the metal compound and diiodine from dichloromethane. The only observed crystalline product was found to be [Ru(bpy)(CO)2(S-SCN)2]⋅I2 with only one NCS⋅⋅⋅I2 halogen bond between I2 and the metal coordinated S atom of one of the thiocyanate ligand. The dangling nitrogen atoms were not involved in halogen bonding. However, computational analysis suggests that there are no major energetic differences between the NCS⋅⋅⋅I2 and SCN⋅⋅⋅I2 bonding modes. The reason for the observed NCS⋅⋅⋅I2 mode lies most probably in the more favourable packing effects rather than energetic preferences between …

Iron (II) isothiocyanate complexes with substituted pyrazines: Experimental and theoretical views on their electronic structure

2015

Abstract Synthesis, structural, magnetic, Mossbauer and thermal studies of isothiocyanate iron (II) complexes with substituted pyrazines (iodo-, bromo- and amino-derivatives) are discussed here. Complexes with iodo- and bromo-derivatives were found to have the composition [Fe(Ipz)2(SCN)2(H2O)2]·2Ipz (1) and [Fe(Brpz)2(SCN)2(H2O)2]·2Brpz (2), whereas in the case of amino-functionalized pyrazine the formation of [Fe(NH2pz)4(SCN)2] (3) was observed. 3D organization of the molecular complexes is stabilized within different hydrogen, halogen and lone pair–π interactions. Spin state of iron (II) ions in 1–3 was determined as high spin by Mossbauer and magnetic measurements. DFT calculations for t…