نتایج جستجو برای: unsymmetrical anhydrides
تعداد نتایج: 3777 فیلتر نتایج به سال:
Hydrophobicities of poly(e-caprolactone) oligomers functionalized with different succinic anhydrides
Different succinic anhydrides were used for modification of hydrophobicities of linear and star-shaped poly (e-caprolactone) oligomers with different molecular weights. Hydroxylterminated poly(e-caprolactone) oligomers were acid-functionalized either with succinic anhydride (SAH) or with alkenylsuccinic anhydrides (ASAs) containing 8 or 18 carbons in their alkenyl chains. Hydrophobicities of th...
We provide a comprehensive account of the 1,3-dipolar cycloaddition reactions of azomethine ylides with carbonyl dipolarophiles. Many different azomethine ylides have been studied, including stabilized and non-stabilized ylides. Of the carbonyl dipolarophiles, aldehydes including formaldehyde are the most studied, although there are now examples of cycloadditions with ketones, ketenes and carbo...
A simple, rapid, solvent-free, room temperature one pot synthesis of benzene ring acylated and demethylated analogues of harmine using acyl halides/acid anhydrides and AlCl(3) has been developed. Eight different acyl halides/acid anhydrides were used in the synthesis. The resulting mixture of products was separated by column chromatography to afford 10- and 12-monoacyl analogues, along with 10,...
A novel method of photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides has been developed. Although the arylation reactions with triarylbismuthines are usually catalyzed by transition-metal complexes, the present arylation of diaryl diselenides with triarylbismuthines proceeds upon photoirradiation in the absence of transition-metal catalysts. ...
A palladium-catalyzed arylation of hydrosiloxanes was developed for the synthesis of symmetrical and unsymmetrical siloxanes. Reactive functional moieties such as hydroxy or cyano groups were able to tolerate the reaction conditions and several novel unsymmetrical siloxanes were synthesized in moderate to high yield.
an efficient one pot multi component synthesis of 1, 4-polyhydroquinoline derivatives through unsymmetrical hantzsch reaction using lanthanum chloride heptahydrate (lacl3.7h2o) from an aromatic aldehyde, ethyl acetoacetate, dimedone and ammonium acetate as a nitrogen precursor in ethanol at room temperature is described. in the present work we report lanthanum chloride heptahydrate remarkably n...
this study was carried out to investigate the effect of esterification on the surface roughness of eastern cottonwood. eastern cottonwood was modified without using any catalyst and solvent at different temperatures and times with two linear chain carboxylic acid anhydrides (acetic anhydride or propionic anhydride). different weight percentage gains (wpgs) were obtained at different conditions....
The mixed anhydrides with N-acyl carbamic acid (IV) were prepared by the reaction of carboxylic acids (Ill) with N-chlorocarbonyl lactams (Ila) or sec. amides (lib). Decarboxylation of IV yielded N-acyl lactams (VI), while symmetrical anhydrides (VII) were obtained by the side reaction of IV with carboxylic acids (III). Aminolysis of IV yielded carboxylic acid amides (IX) in high yield and puri...
Polyfluoro-substituted unsymmetrical biaryl ethers were synthesized via a novel Ni-catalyzed cross-coupling reaction of polyfluoroarenes with arylboronic acids and oxygen. The polyfluorinated arenes presumably captured the phenoxide intermediate efficiently, which made the oxygen-insertion proceed smoothly via the S(N)Ar protocol. The (18)O labeling experiment demonstrated that the oxygen intro...
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