Search results for "Phenyl group"

ChemInform Abstract: Substituent Effect on Oxidative Cyclization of Aldehyde Thiosemicarbazones with Ferric Chloride.

2010

The reactivity of aldehyde thiosemicarbazones 1 with ferric chloride solutions was examined. When compounds 1 are not substituted on the N-2 nitrogen atom formation of 1,3,4-thiadiazole 3 heterocyclic ring was observed. In contrast 1,2,4-triazoline 4 and/or 1,3,4-thiadiazoline 5 heterocyclic rings were afforded when N-2 nitrogen atom carried a methyl or a phenyl group. The reaction mechanism is also discussed.

Alkyl and Aryl Substituted Corroles. 1. Synthesis and Characterization of Free Base and Cobalt Containing Derivatives. X-ray Structure of (Me4Ph5Cor)…

2001

The synthesis, spectroscopic properties, and electrochemistry of six different alkyl- and aryl-substituted Co(III) corroles are presented. The investigated compounds contain methyl, ethyl, phenyl, or substituted phenyl groups at the eight β-positions of the corrole macrocycle and four derivatives also contain a phenyl group at the 10-meso position of the macrocycle. Each cobalt corrole undergoes four reversible oxidations in CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate and exists as a dimer in its singly and doubly oxidized forms. The difference in potential between the first two oxidations is associated with the degree of interaction between the two corrole units of the dimer …

Non-steroidal Anti-inflammatory Agents, Part 24[1] Pyrrolidino Enaminones as Models to Mimic Arachidonic Acid

1997

The pyrrolidino enaminones, with the carboxylic acid chain fixed at the nitrogen, inhibit cyclooxygenase more potently or selectively than 5-lipoxygenase. According to the structure-activity relationships discussed the potency depends significantly on the chain length of the carboxylic acid, the substitution pattern of the heterocyclic moiety and of the phenyl group. Compound 4c is the most efficient inhibitor of cyclooxygenase. For the binding profile the unfolded conformation of arachidonic acid and the energy-minimized conformations of flurbiprofen, diclofenac, ML 3000, and lead compound 4a were compared. In addition to known structural features, similar distances of the carboxylic acid …

Electrochemical oxidation of 2,4,5-triaryl-substituted pyrroles.II. Oxidative dimerization of 4,5-diphenyl-2-mesitylylpyrrole

1989

2,4,5-Triaryl-substituted pyrroles lead, upon chemical or electrochemical oxidation, to an intermediate β-β'-dimer, which, in the course of the reaction, undergoes further oxidation to a tetracyclic derivative. To improve the selectivity towards the uncyclized dimer the oxidation of a triarylpyrrole in which the ortho positions of the phenyl group in position 2 are hindered by the presence of methyl groups was attempted. The cyclization was hindered, but an α-β'-dimer was obtained as the major product. An unexspected isomeric α-β'-dimer, in which the mesitylyl group is shifted into the β position of the pyrrole ring which undergoes the oxidation, was obtained in minor amounts. Electroanalyt…

Ab Initio Study of Stereo- and Regioselectivity in the Diels−Alder Reaction between 2-Phenylcyclopentadiene and α-(Methylthio)acrylonitrile

1997

Ab initio molecular orbital calculations have been used to investigate the Diels−Alder reaction between 2-phenylcyclopentadiene and α-(methylthio)acrylonitrile. Geometry optimizations were performed with the RHF/3-21G, RHF/3-21G*, and RHF/6-31G* calculations while the correlation energy has been calculated at MP2 and MP3 levels. Four asynchronous transition structures corresponding to the formation of different stereoisomers and regioisomers associated with the four reaction channels have been located. The observed endo/exo stereoselectivity and para/meta regioselectivity are correctly described at all levels of calculation, and the calculated activation energies reflect accurately the rela…

Redox properties of nitrophenylporphyrins and electrosynthesis of nitrophenyl-linked Zn porphyrin dimers or arrays

2014

Five nitrophenylporphyrins were investigated as to their electrochemical properties in CH 2 Cl 2 containing 0.1 M TBAP. The investigated compounds are represented as ( NO 2 Ph )x Ph 4-x PorM , where Por represents the dianion of the porphyrin macrocycle, Ph is a phenyl group on meso-position of the macrocycle, NO 2 Ph is a meso-substituted nitrophenyl group, M = 2 H , Pd II or Zn II and x = 1 or 2. Each porphyrin undergoes an initial one electron reduction at E1/2 = -1.07 to -1.12 V where the added negative charge is almost totally localized on the meso-nitrophenyl group of the compound. This reversible reduction is then followed by one or more irreversible reductions of the nitrophenyl an…

1981

The proton spin-lattice relaxation time T1 was determined at 13,8, 55,2, and 90 MHz in polystyrene (PS-d0) and polystyrene deuterated at the chain (PS-d3) and the phenyl groups (PS-d5), respectively, at temperatures between −130 and +230°C. Furthermore, T1 was measured in isotopic mixtures of PS-d3 and fully deuterated PS-d8 where a separation into intramolecular and intermolecular contributions was possible through the deuteron dilution technique. Above 130°C, various distributions of correlation times provide a semiquantitative understanding of the different motins seen by the protons of the partially deuterated systems. Rotating frame relaxation times in PS-d3 and PS-d5 reveal librationa…