نتایج جستجو برای: anhydrides
تعداد نتایج: 2251 فیلتر نتایج به سال:
An intermolecular nickel-catalyzed addition reaction has been developed where phthalic anhydrides react with alkynes to afford substituted isocoumarins. A mechanistic rationale is proposed, implying reductive elimination of Ni(0) promoted by ZnCl(2) cocatalyst as the key step of the catalytic cycle.
Unsubstituted cyclic imides were synthesized from a series of cyclic anhydrides, hydroxylamine hydrochloride (NH2OH.HCl), and 4-N,N-dimethylamino-pyridine (DMAP, base catalyst) under microwave irradiation in monomode and multimode microwaves. This novel microwave synthesis produced high yields of the unsubstituted cyclic imides for both the monomode (61 - 81%) and multimode (84 - 97%) microwaves.
The synthesis of amide C N bonds through nucleophilic acyl substitutions constitutes one of the most fundamental transformations in chemical synthesis. Recently, the Staudingertype ligation of carboxylic acid derivatives (e.g., acid chlorides, anhydrides, acyl selenides, and thioesters) and azides has become a preeminent strategy for amide C N bond construction (Scheme 1a). However, the generat...
the treatment equimolar quantities of carboxylic acids with acid chlorides in the presence of zno brings abouthighly efficient unsymmetrical anhydrides at room temperature in solvent-free condition. reactivity trendsfavored formation of the product using both electron deficient and rich aryl acids and acid chlorides.
N labeled soluble metalloand metal-free phthalocyanines are described for the first time. The complexes were synthesized starting from phthalic anhydride derivatives using 98% N enriched urea. The effects of the substitution pattern, aggregation, and coordinated metal on N chemical shifts in liquid state NMR were studied.
A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, along with minor quantities of N-acyl-tryptamines and 8-acyl analogues of N-acyltryptamines.
A new method for the enantioselective reductive coupling of aryl alkenes with activated carboxylic acid derivatives via copper hydride catalysis is described. Dual catalytic cycles are proposed, with a relatively fast enantioselective hydroacylation cycle followed by a slower diastereoselective ketone reduction cycle. Symmetrical aryl carboxyclic anhydrides provide access to enantioenriched α-s...
An efficient carboesterification of alkenes with anhydrides promoted by MnO2 has been developed to afford functionalized γ-lactones in good to excellent yields. This method shows a broad substrate scope and provides a valuable and convenient synthetic tool for constructing γ-lactones.
Mechanisms of double carbonylation reactions catalyzed by palladium complexs to give a-keto amides and a-keto esters, stoichiometric double carbonylation of ally1 carbonates, and cyclization carbonylation . of 3-butenoic acid to give cyclic anhydrides are discussed as combination of elementary processes of organometallic reactions.
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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