نتایج جستجو برای: bromides
تعداد نتایج: 13171 فیلتر نتایج به سال:
Employing (2-pyridyl)acetone as a new supporting ligand, the copper-catalyzed coupling reactions of aryl chlorides, aryl bromides, and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. This reaction displays great functional groups compatibility and excellent reactive selectivity.
Tetrafluoroethylene-containing azides are accessed in two steps (one pot) from tetrafluoroalkyl bromides by metalation and reaction with electrophilic azides. Subsequent copper(i)-catalyzed azide-alkyne cycloaddition afforded N-tetrafluoroethyl and N-tetrafluoroethylene 4-substituted 1,2,3-triazoles. In addition, the protocol for the synthesis of 4,5-disubstituted 1,2,3-triazoles is presented.
An efficient palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides has been developed. The reaction proceeds under mild reaction conditions with high efficiency and excellent functional group tolerance, even towards formyl and hydroxy groups. Preliminary mechanistic studies reveal that a secondary trifluoromethylated alkyl radical is involved in the reaction.
On reading some early notes1 on "Sulphonal, I came to the conclusion that the drug might prove of great use in certain cases of epilepsy, especially in those which had n?t been much benefited by the bromides. In epilepsy we have to treat both cause and effect; for lf the fits have been numerous, and if the cause, which
2-Allyl-substituted thiophenes and furans are synthesised efficiently in a direct procedure using 2-heteroaryllithium reagents and allyl bromides and chlorides catalysed by ligand-free copper(i). The reactions take place under mild conditions, with excellent α-selectivity, high functional group tolerance and good yields for the SN2 products.
A regioselective synthesis of 6-ω-alkenyluridines 3, precursors of potent antiviral and antitumor cyclonucleosides 5, is described. While ω-alkenyl halides do not alkylate 6-lithiouridine, compounds 3 were prepared in a regioselective manner by sequential treatment of 6-methyluridine 2 with LTMP or LDA (4 equiv) in THF at -30 °C followed by alkylation with ω-alkenyl bromides.
We report the design of bisarylmethylene bromides as a new class of rigid, distance-matching cysteine cross-linkers. By cross-linking a peptide dual inhibitor of Mdm2/Mdmx containing cysteines at i,i+7 positions, dramatic enhancement in cell permeability was achieved, along with increased helicity and biological activity.
An efficient room-temperature palladium-catalyzed direct 2-arylation of benzoxazoles with aryl bromides is presented. The Pd(OAc)2/NiXantphos-based catalyst enables the introduction of various aryl and heteroaryl groups, via a deprotonative cross-coupling process (DCCP) in good to excellent yields (60-99%).
In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class...
Ni-catalyzed ketone formation through mild reductive coupling of a diverse set of unactivated alkyl bromides and iodides with particularly aryl acid anhydrides was successfully developed using zinc as the terminal reductant. These conditions also allow direct coupling of alkyl iodides with aryl acids in the presence of Boc(2)O and MgCl(2).
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