نتایج جستجو برای: alternative substituents
تعداد نتایج: 311992 فیلتر نتایج به سال:
esters of phthalates, mainly applied as plasticizer, cause several human health and environment hazards. phthalates are widely used in pharmaceutical products, cosmetics, as well as other plastic commercial products, and can penetrate in foods, water dusts, and air leading to ingestion and inhalation exposure followed by skin absorption for human. these compounds cause serious adverse effect...
After Mallory described in 1964 the use of iodine as catalyst for the photochemical cyclisation of stilbenes, this reaction has proven its effectiveness in the synthesis of phenanthrenes, other PAHs and phenacenes with a surprisingly large selection of substituents. The "early age" of the reaction was reviewed by Mallory in 1984 in a huge chapter in the Organic Reactions series, but the develop...
The present paper proposes a reliable alternative for the increasing stability of polypropylene (PP) by modified polyhedral oligomeric silsesquioxanes (POSS). chemiluminescence measurements and FTIR records point complementarily out determinant influence substituents on progress oxidation during accelerated degradation caused ?-irradiation. main kinetic approach acting in radiation-induced agin...
Two strains of bacteria capable of carrying out the O-methylation of phenolic compounds, one from the gram-positive genus Rhodococcus and one from the gram-negative genus Acinetobacter, were used to examine the O-methylation of phenols carrying fluoro-, chloro-, and bromo-substituents. Zero-order rates of O-methylation were calculated from data for the chloro- and bromophenols; there was no sim...
A facile synthetic route towards phenylene vinylene systems with methyl substituents at the vinyl linkages is demonstrated through palladium catalyzed Heck coupling of 1,4-diisopropenylbenzene with aryl bromides. The coupling leads to a series of model compounds that feature, in some cases, direct access to a trans-configuration at the double bonds. The oxidative stability of these systems is s...
Dithiomaleimides (DTMs) with alkyl substituents are shown to be a novel class of highly emissive fluorophores. Variable solubility and further functionalization can easily be tailored through the choice of N and S substituents. Inclusion of a DTM unit into a ROP/RAFT initiator or insertion into the disulfide bond of salmon calcitonin (sCT) demonstrates the utility for fluorescent labeling of po...
The effect of alkyl substituents on the C-phenyl and/or the N-Phenyl ring of benzophenylhydroxamic acid on their molecular structure and hydrogen bonding has been investigated. The predominant configuration in CHCl3 is determined by steric and electronic effects. Substituents on the C-phenyl ring favor the cis configuration, while substituents in the N-phenyl ring favor a trans c...
Esters of phthalates, mainly applied as plasticizer, cause several human health and environment hazards. Phthalates are widely used in pharmaceutical products, cosmetics, as well as other plastic commercial products, and can penetrate in foods, water dusts, and air leading to ingestion and inhalation exposure followed by skin absorption for human. These compounds cause serious adverse effect...
the effect of alkyl substituents on the c-phenyl and/or the n-phenyl ring of benzophenylhydroxamic acid on their molecular structure and hydrogen bonding has been investigated. the predominant configuration in chcl3 is determined by steric and electronic effects. substituents on the c-phenyl ring favor the cis configuration, while substituents in the n-phenyl ring favor a trans configuration. t...
A highly efficient Cu-catalyzed ring expansion reaction of 2H-azirines with terminal alkynes has been developed. This transformation provides a powerful method for the synthesis of 3-alkynyl polysubstituted pyrroles under mild conditions in good yields. The direct transformation process, specific selectivity, and good tolerance to a variety of substituents make it an alternative approach to the...
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