نتایج جستجو برای: multicomponent reaction
تعداد نتایج: 421340 فیلتر نتایج به سال:
a green and convenient method for the synthesis of 14-aryl-14h-dibenzo[a,i]xanthene-8,13-diones and spiro[dibenzo[a,i]-xanthene-14,3'-indoline]-2',8,13-triones in the presence of a catalytic amount of cellulose sulfuric acid (csa) as an efficient biopolymer-based catalyst under solvent-free conditions at 100 °c is described. the condensation reactions of β-naphtol, 2-hydroxynaphthalene-1,4-dion...
Comprising abundant interfaces, multicomponent heterostructures can integrate distinct building blocks into single entities and yield exceptional functionalities enabled by the synergistic components. Here we report an efficient approach to construct one-dimensional metal/sulfide heterostructures by directly sulfuring highly composition-segregated platinum-nickel nanowires. The heterostructures...
al-mcm-41 nanoreactors is found to be a remarkable efficient catalyst for one-pot multicomponent cyclocondensation of benzil, aniline or ammonium acetate and aromatic aldehydes for the synthesis of polysubstituted imidazoles under solvent-free conditions. the reaction was efficiently promoted by 10 mg nano-al-mcm-41 and the heterogeneous catalyst was recycled for four runs in this reaction with...
An Ugi multicomponent reaction based two-step strategy was applied to generate medium-sized rings. In the first linear expansion phase, a series of diamines reacted with cyclic anhydrides to produce different lengths of terminal synthetic amino acids as the starting material for the second phase. The Ugi-4-center 3-component reaction was utilized to construct complex medium-sized rings (8-11) b...
Visible-light photoredox catalysis has been utilized in a new multicomponent reaction forming β-functionalized δ-diketones under mild conditions in an operationally convenient manner. Single-electron reduction of in situ generated carboxylic acid derivatives forms acyl radicals that react further via 1,2-acylalkylation of olefins in an intermolecular, three-components cascade reaction, giving v...
[reaction: see text] The synthesis of free alpha-chiral amines by a one-pot multicomponent procedure from commercially available starting materials is described. This enantioselective reaction involves a catalytic asymmetric addition of dialkylzinc reagents to N-diphenylphosphinoylimines with use of an air-stable precatalyst complex 1. The alpha-chiral amines are prepared with a one-pot procedu...
A series of nine novel 3-tetrazolylmethyl-azepino[4,5-b]indol-4-ones were prepared in moderate to good overall yields in only two reaction steps. The first step consisted of a one-pot sequential process of an Ugi-azide multicomponent reaction, N-acylation and SN2 to give the xanthates. The second step was an intramolecular cyclization under free radical conditions. Also, their binding modes hav...
A microwave-assisted, multicomponent protocol for the synthesis of substituted 3,4-dihydroquinazolinones via a novel cascade imine/cyclization/aza-Henry reaction sequence is reported. Starting from o-formyl carbamates, a series of structurally diverse 3,4-dihydroquinazolinones was synthesized via a cyclic iminium ion intermediate in moderate to excellent yields. Notably, the reaction is fast, f...
5-Aminopyrazole-4-carbonitrile and ethyl 5-aminopyrazole-4-carboxylate, as potential trifunctional building blocks are introduced in a facile, chemo- and regioselective multicomponent assembly of imidazo[1,2-b]pyrazoles via the Groebke-Blackburn-Bienaymé reaction (GBB reaction). Besides the synthetic elaboration of a green-compatible isocyanide-based access in three-component mode, we describe ...
We describe the palladium-catalyzed multicomponent synthesis of 2-imidazolines. This reaction proceeds via the coupling of imines, acid chlorides and carbon monoxide to form imidazolinium carboxylates, followed by a decarboxylation. Decarboxylation in CHCl(3) is found to result in a mixture of imidazolinium and imidazolium salts. However, the addition of benzoic acid suppresses aromatization, a...
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