نتایج جستجو برای: alkylation
تعداد نتایج: 5091 فیلتر نتایج به سال:
In this paper we describe new multi-catalysis cascade (MCC) reactions for the one-pot synthesis of highly functionalized non-symmetrical malonates. These metal-free reactions are either five-step (olefination/hydrogenation/alkylation/ketenization/esterification) or six-step (olefination/hydrogenation/alkylation/ketenization/esterification/alkylation), and employ aldehydes/ketones, Meldrum's aci...
DNA damage is unavoidable, and organisms across the evolutionary spectrum possess DNA repair pathways that are critical for cell viability and genomic stability. To understand the role of base excision repair (BER) in protecting eukaryotic cells against alkylating agents, we generated Schizosaccharomyces pombe strains mutant for the mag1 3-methyladenine DNA glycosylase gene. We report that S. p...
Alkylation of ribonuclease A by iodoacetamide at pH 5.5 yields two products: inactive 3-carboxamidomethylhistidine12.ribonuclease and fully active S-carboxamidomethylmethionine ribonuclease. No derivative substituted at histidine-119 was detected. This is in marked contrast to the products obtained on alkylation by iodoacetate at pH 5.5. The rate of alkylation of histidine in ribonuclease by io...
Amorphous alumino phosphate (AP) and zirconium phosphate (ZP) materials possessing an ordered nanoporosity have been successfully synthesized by a hydrothermal method using a P123 block co-polymer as the structure directing agent. The materials exhibited excellent catalytic activity towards selective alkylation of phenol with cyclohexanol, where AP showed as high as 100% selectivity to produce ...
By incubating Ehrlich cells with isotopically labeled nitrogen mustards the relation between the extent of alkylation of cell constituents and the reduction of growth potential can be studied. Data obtained by such studies show that both CQM and HN2 react with a wide variety of cell constituents. Of the macromolecular constituents, the proteins undergo the greatest amount of alkylation, but the...
Alkylation-induced O(6)-methylguanine (O(6)MeG) DNA lesions can be mutagenic or cytotoxic if unrepaired by the O(6)MeG-DNA methyltransferase (Mgmt) protein. O(6)MeG pairs with T during DNA replication, and if the O(6)MeG:T mismatch persists, a G:C to A:T transition mutation is fixed at the next replication cycle. O(6)MeG:T mismatch detection by MutSalpha and MutLalpha leads to apoptotic cell de...
An improved method for the asymetric alkylation of 3-bromooxindoles with α-arylated malonate esters is described. The asymmetric alkylation demonstrated was achieved up to 70% ee utilizing a copper(II) bis(phosphine) complex.
The current work utilizes the ab initio density functional theory (DFT) to develop a molecular level of the mechanistic understanding on the phenol alkylation in the presence of a cation-exchange resin catalyst, Amberlyst-15. The catalyst is modeled with the benzene sulfonic acid, and the effect of this acid on olefins such as isopropene (i-Pr) and tributene (t-Bu) in a phenol solution mimics t...
abstract among synthetic carriers, dendrimers with the more flexible structure have attracted a great deal of researchers' attention in the field of gene delivery. followed by the promising results upon hydrophobic modification on polymeric structures in our laboratory, alkylcarboxylated poly (propylenimine)-based carriers were synthesized by nucleophilic substitution of amines with alkyl moiet...
The kinetics of the liquid-phase alkylation guaiacol (G) with cyclohexene (CH) over Amberlyst 36 resin was studied using Langmuir–Hinshelwood–Hougen–Watson (LHHW) heterogeneous kinetic models. Catalytic tests were performed in a batch reactor, solvent-less conditions, at 363 K, 1 bar, 600 RPM, G:CH molar ratio equal to 5 total volume 30 ml and 1.5 g solid catalyst. G CH formed cyclohexyl-2-meth...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید