نتایج جستجو برای: alkylation
تعداد نتایج: 5091 فیلتر نتایج به سال:
A catalytic, enantioselective γ-alkylation of α,β-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- and enantioselective iridium-catalyzed α-alkylation of an extended enolate, and a subsequent translocation of chirality to the γ-position via a Cope rearrangement.
We describe here the determination of the alkylation rate of a set of organic superbases by iodomethane in DMF using a microfluidic continuous flow reactor. Surprisingly, log k(Alkylation) follows the inverse trend of pK(BH+) of the base. Mayr's equation allows a more quantitative approach. From a synthetic point of view, TMGN and BEMP are demonstrated to be the best choices.
Background: DNA-alkyltransferases repair mutagenic and carcinogenic alkylation DNA lesions. Results: A thermophilic archaeal DNAalkyltransferase is degraded after alkylation in vivo. A novel assay is applied to study its activity in vitro. Conclusion: The archaeal DNA-alkyltransferase shows structure, activity and in vivo regulation similar to its human homolog. Significance: The function and r...
In this paper, a simple and highly efficient ruthenium-catalyzed direct C3 alkylation of indoles with various α,β-unsaturated ketones without chelation assistance has been developed. This novel C-H activation methodology exhibits a broad substrate scope such as different substituted indoles, pyrroles, and other azoles. Further synthetic applications of the alkylation products can lead to more a...
Nitrogen doped graphene was modified by N-alkylation using a combination of phase transfer catalysis and microwave irradiation. The resulting derivatives of N-doped graphene were analysed showing that the bandgap of the material varied depending on the alkylation agent used.
The in vivo alkylation of heme by the antimalarial trioxaquine DU1301 afforded covalent heme-drug adducts that were detected in the spleens of Plasmodium sp.-infected mice. This result indicates that the alkylation capacities of trioxaquines in mammals infected with Plasmodium strains are similar to that of artemisinin, a natural antimalarial trioxane-containing drug.
The effects of steroid-induced modifications of chromatin structure on the extent and sites of chloroethylnitrosourea binding to chromatin were studied using log-phase HeLa cells. The cells were exposed to 0.1 to 2.0 /¿Mhydrocortisone for 22 hr; this resulted in depressed DMA synthesis while transcriptional activity was stimulated. Hydrocortisone had no effect upon cellular or nuclear uptake o...
Several pathological conditions involve alterations in expression of neuronal nicotinic acetylcholine receptors (nAChRs). Although some studies have addressed processes involved with muscle nAChR expression, knowledge of the regulation of neuronal nAChRs is particularly sparse. The following studies were designed to investigate cellular mechanisms involved with expression of neuronal alpha3beta...
A kinetic study of the alkylating potential of potassium sorbate (S)-a food preservative used worldwide-in 7:3 water/dioxane medium was performed. The following conclusions were drawn: (i) Potassium sorbate shows alkylating activity on the nucleophile 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases, (ii) The NBP alkyl...
A general, simple, practical and convenient method has been described for the synthesis of anesthetic drug thiopental using thiourea in the presence of sodium ethoxide. Anesthetic drug of thiopental was prepared in two stages; during the first stage, the alkylation of mthyl cyanoacetate was performed which was then to be followed by cyclization. Alkylation of methyl cyanoacetate which was perfo...
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