Search results for "deriva"

The Preparation of 1,3-Divinylparabanic Acid (1,3-Divinylimidazoletrione) and its 4-Imino Derivative

1962

Intramolecular cyclization of chloral allyl hemiacetal under the action of the Fe(CO)5-DMF system

1999

Chloral allyl hemiacetal undergoes cyclization in the presence of the Fe(CO)5-DMF system to form 3,3,5-trichloro-2-hydroxytetrahydropyran rather than a butyrolactone derivative.

ChemInform Abstract: Reaction of Diphenyldiazomethane with N-Methyloxy- and N-Ethyloxycarbonyl-N-(2,2,2-trichloroethylidene)amines.

2010

Reaction of the title imines with diphenyldiazomethane gives a Δ3-1,3,4-triazoline, which leads, after loss of dinitrogen, to a transient azomethine ylide. Subsequent elimination of ethyl or methyl chloroformate gives the unexpected 1,1-diphenyl-4,4-dichloro-2-aza-1,3-butadiene.

Heterocyclic rearrangements. Phenylhydrazones andN-methyl-N-phenylhydrazones of 3-acylisoxazoles

1983

The reaction of 3-benzoyl-5-phenylisoxazole (4) and 3-acetyl-5-methylisoxazole (5) with phenylhydrazine and N-methyl-N-phenylhydrazine has been investigated and the reactivity of (E)- and (Z)-phenylhydrazones and N-methyl-N-phenylhydrazones has been studied.

ChemInform Abstract: The Pyrrole Moiety as a Template for COX-1/COX-2 Inhibitors.

2000

ChemInform Abstract: Ru(bpy)2Cl2: A Catalyst Able to Shift the Course of the Photorearrangement in the Boulton-Katritzky Reaction.

2016

Abstract The Boulton–Katritzky reaction represents one of the most popular and efficient strategies used to realize azole-into-azole conversions. For example, under different experimental conditions, it allows the rearrangement of Z-arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazoles (1) into 2-aryl-4-benzoylamino-5-phenyl-2H-1,2,3-triazoles (2) in very high yields. Moreover, we have recently realized this conversion also by UV-photostimulation. Now we have enlarged the scope of the reaction irradiating with visible or UV light an acetonitrile solution of some Z-arylhydrazones (1a–e) in the presence of catalytic amounts of Ru(bpy)2Cl2. We have observed the unexpected formation of the 1-a…

New Glass Capillary Gas-Chromatographic Methods for Metabolites in Urine and Serum

1981

The analytical system suggested in this paper is a further development of pre-chromatographic methods and of column switching techniques described in previous papers1,2,3.In order to use modern gas-chromatographic techniques for the determination of metabolites in urine and serum quick and reliable pre-chromatographic methods for extraction, concentration and derivatization must be developed which give final (dosage) volumes of 5 to 10 μl with starting sample volumes of 0.1 ml of urine or 5 ml of serum as described by Dunges4.

Validation of Methylmercury Determinations in Aquatic Systems by Alkyl Derivatization Methods for GC Analysis Using ICP-IDMS

2001

Isotope dilution mass spectrometry (IDMS), using an inductively coupled plasma quadrupole mass spectrometer (ICPMS) and a species-specific methylmercury spike was applied to validate the commonly used GC method for methylmercury (MeHg+) determination, which is based on the formation of volatile methylethylmercury by derivatization with NaBEt4. The spike compound, Me201Hg+, was synthesized by reaction of 201Hg-enriched mercury chloride with methylcobalamin. By analyzing different environmental aquatic samples, it was found that in most cases, transformation of MeHg+ into elemental mercury (Hg0) took place. From investigations of synthetic solutions, it could be followed that halide ions are …

Amphetamine and Methamphetamine Determinations in Biological Samples by High Performance Liquid Chromatography. A Review

1994

Abstract This critical review shows the different high performance liquid chromatography methods proposed for amphetamine and methamphetamine determinations. It is directed mainly towards sample clean up and derivatizations steps, because of their significance in such determinations.

ChemInform Abstract: Synthesis and Electrode Reactions of Difluorogermanium(IV) Porphyrins. Molecular Stereochemistry and Crystal Structure of Difluo…

1988

The difluorogermanium(IV) porphyrins [GeF2(P)][P = 2,3,7,8,12,13,17,18-octaethylporphyrinate(2–)(oep), 5,10,15,20-tetraphenylporphyrinate(2–)(tpp), or 5,10,15,20-tetra-p-tolylporphyrinate(2–)(tptp)] have been prepared by reacting hydrogen fluoride with the appropriate dichloro derivative [GeCl2(P)]. The complexes were characterized by elemental analysis, 1H n.m.r., i.r., and u.v.–visible spectroscopy. The electrochemical behaviour was investigated in non-aqueous media while spectroelectrochemistry and e.s.r. were used to characterize the oxidized and reduced complexes. Each complex could be reversibly oxidized or reduced by one electron. In each case these electron additions or abstractions…