نتایج جستجو برای: multicomponent synthesis
تعداد نتایج: 417971 فیلتر نتایج به سال:
Ring-opening of cyclic sulfamidates with propargylic sulfonamides yielded substrates for a gold-catalyzed cyclization to yield tetrahydropyrazines. Manipulation of the tetrahydropyrazines, by reduction or using multicomponent reactions, yielded piperazine scaffolds in which substitution of the carbon atoms was varied. Such scaffolds may have value in the synthesis of novel screening compounds w...
We discovered a novel organocatalysed multicomponent domino Knoevenagel-aza-Michael-cyclocondensation reaction leading to an unprecedented straightforward synthesis of 1,5-diazabicyclo[3.3.0]octane-2,6-diones. The specific capability of the (DHQ)2PHAL organocatalyst in this process was also highlighted to eventually furnish the corresponding bicyclopyrazolidinones with up to 96 : 4 er.
In the recent past, the design and synthesis of peptide mimics (peptidomimetics) has received much attention. This because they have shown in many cases enhanced pharmacological properties over their natural peptide analogues. In particular, the incorporation of cyclic constructs into peptides is of high interest as they reduce the flexibility of the peptide enhancing often affinity for a certa...
A one-pot surfactant-free method has been successfully developed to synthesize Bi(2)MoO(6) boxes using MoO(3) nanorods as templates. A formation mechanism involving the nanoscale Kirkendall effect has been proposed. Our work demonstrates the generic feature of a mild solution-phase-mediated nanoscale Kirkendall effect for the synthesis of multicomponent materials with box-like structures.
The multicomponent synthesis of α,β-disubstituted N-sulfonyl β-amino esters is described. It involves a zinc-mediated, cobalt-catalyzed three-component reaction between sulfonylimines, acrylates and organic bromides. A possible mechanism is proposed, emphasizing the intermediate formation of an organocobalt as the initiator of a Mannich-like process.
The synthesis of unnatural pyrrolizidines has been studied using a multicomponent-domino process involving proline or 4-hydroxyproline esters, an aldehyde and a dipolarophile. The formation of the iminium salt promotes the 1,3-dipolar cycloaddition affording highly substituted pyrrolizidines under mild conditions and high regio- and diastereoselectivities.
The paper presents an application of the asymmetry approach to spirooxindoles via Brevicolline, Cinchonidine or Cinchonine catalyzed one-pot multicomponent synthesis. Brevicolline, in comparison with Cinchonidine or Cinchonine, catalyzes the reaction of isatins, acetylacetone/ethyl 3-oxobutanoate and malononitrile, with the formation of spiro[oxindole-3,4'-4'H-pirane] derivatives in an opticall...
Three UV spectrophotometric methods have been developed, simultaneous equation method, multicomponent analysis (II) and derivative spectroscopy method (III). The absorption maxima of the drugs were found to be 247, 259 and 272 nm, respectively for efavirenz, tenofovir disoproxil fumarate and lamivudine in methanol:water (50:50) solvent system. Efavirenz, tenofovir disoproxil fumarate and lamivu...
A multicomponent reaction of triazoloketones, primary amines, and 4-nitrophenyl azide was developed for the synthesis hitherto unknown angularly fused/linear bitriazoles. The two-stage mechanism well proven by isolation intermediate. This sequential consists Cornforth rearrangement triazolization, which has also been demonstrated in a one-pot manner.
BACKGROUND Mechano heterocyclic chemistry (MCH) is a recent quickly growing technique in the synthesis of heterocycles and draws the attention of heterocyclic chemists towards the uses of grindstone technique in a solvent free green efficient synthesis of many heterocyclic systems. On the other hand, multicomponent approach has opened the door for the rapid and efficient one-step procedures to ...
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