نتایج جستجو برای: unsymmetrical anhydrides
تعداد نتایج: 3777 فیلتر نتایج به سال:
A palladium complex derived from Pd2(dba)3 and dppp catalyzes the addition reaction of aroyl/heteroaroyl acid anhydrides to norbornenes, giving 2-aroyl/heteroaroyl-3-aroyloxy/heteroaroyloxy-bicyclo[2,2,1]heptanes. The C-O bond of acid anhydride is cleaved, and the aroyl/heteroaroyl and aroyloxy/heteroaroyloxy groups are added to alkenes. trans-Adducts are selectively obtained with the endo-benz...
Coenzyme A esters of all-trans- and 13-cis-retinoic acid were synthesized for use in studying vitamin A metabolism. The esters were obtained by two different synthetic methods starting from retinoic acids, which were converted to activated succinimidyl esters or anhydrides. These in turn were coupled with coenzyme A to form their respective thioesters. The retinoyl coenzyme A esters were purifi...
Two sensitive, selective, economic, and validated spectrofluorimetric methods were developed for the determination of ebastine (EBS) in pharmaceutical preparations depending on reaction with its tertiary amino group. Method I involves condensation of the drug with mixed anhydrides (citric and acetic anhydrides) producing a product with intense fluorescence, which was measured at 496 nm after ex...
“Maghnite” a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for polymerization of many vinylic and heterocyclic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structure compositions of both “Maghnite” and “H-Maghnite” have been developed. This catalyst was used for the polycondensation of the tetrahydrofuran with phthal...
Acylation of anisole with 2-phenylbutanoic acid derivatives, over zeolite catalysts, gives the corresponding 4-acyl derivatives with high regioselectivity. In an analogous way, 2,3-dihydrobenzofuran reacts with acid anhydrides or chlorides in the presence of catalytic quantities of zeolites to give the corresponding 5-acyl-2,3-dihydrobenzofurans. The zeolite can be recovered, regenerated and us...
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