نتایج جستجو برای: secondary reaction
تعداد نتایج: 701613 فیلتر نتایج به سال:
Acceptorless dehydrogenation of alcohols, an important organic transformation, was accomplished with welldefined and inexpensive iron-based catalysts supported by a cooperating PNP pincer ligand. Benzylic and aliphatic secondary alcohols were dehydrogenated to the corresponding ketones in good isolated yields upon release of dihydrogen. Primary alcohols were dehydrogenated to esters and lactone...
The anti-arthritic activity of four superoxide dismutases (SODs) has been compared by using the adjuvant-induced polyarthritis rat model. Many of the clinical signs observed in the rat closely resemble those of human rheumatic diseases and the Fiessinger-Leroy-Reiter syndrome. An original protocol and various approaches allowed study of the evolution of long term (30-90 days) SOD treatment. Res...
Nuclear reactions initiated by laser-accelerated particle beams are a promising new approach to many applications, from medical radioisotopes to aneutronic energy production. We present results demonstrating the occurrence of secondary nuclear reactions, initiated by the primary nuclear reaction products, using multicomponent targets composed of either natural boron (B) or natural boron nitride...
The preparation of peptide thioesters using Fmoc chemistry requires their synthesis as amides flowed by an N -> S-acyl shift reaction. Recently, bis(2-sulfanylethyl)amino-trityl-polystyrene (SEA) resin has been reported (1, 2), where the peptide is synthesized as a secondary amide, and the N -> S-acyl shift occurs by reaction of one of the two 2-sulfanylethyl groups. The PAET resin described he...
Neurocognitive motor tasks have been shown to have an effective relationship with athletic performance and musculoskeletal injuries. Cognitive changes following anterior cruciate ligament reconstruction surgery may lead to adverse knee biomechanical changes and an increased risk of secondary injury. This study aimed to compare the kinetics of athletes with a history of ACL reconstruction and th...
Compaction matters: SN2 substitution represents an important class of reaction for both chemical and biological systems. The ability to assess enzymatic transition state structure within this class of reaction remains a major experimental challenge. Here, we comment on and compare the relative impact of compaction along the axis of reaction to the impact of an orthogonal CH···O hydrogen bonding...
We have developed an efficient procedure for the easy and straightforward preparation of functionalized dihydropyridazines as highly enantiopure materials by reaction of pyruvaldehyde 2-tosyl hydrazone with a variety of α,β-unsaturated aldehydes using a chiral secondary amine as catalyst. The overall process consists of a cascade reaction involving an initial aza-Michael reaction, in which the ...
abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...
The reaction of 17,17-dichloro-androst-16(E)-chloromethylene with secondary amine base afforded substitution products exocyclic D-ring ketones, in contrast to the alkaline which cleaved steroidal des-D formyl alkyne. alkyne was employed prepare annulated isoxazolo steroid via 1,3-dipolar nitrile oxide cycloaddition reaction.
sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (saspspe) is employed as a recyclable catalyst for the silylation of hydroxyl groups. a good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of saspspe at room temperature with short rea...
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