نتایج جستجو برای: quaternary ammonium
تعداد نتایج: 37064 فیلتر نتایج به سال:
A novel class of tartaric acid-derived N-spiro quaternary ammonium salts was synthesised starting from known TADDOLs. These compounds were found to catalyse the asymmetric α-alkylation of glycine Schiff bases with high enantioselectivities and in good yields.
Repeated reaction between a chiral quaternary ammonium dimer and disodium disulfonate gave a chiral ionic polymer, which showed excellent catalytic activity in the asymmetric benzylation of N-diphenylmethylene glycine tert-butyl ester.
A fluorescent probe (QA) based on quinine bearing two quaternary ammonium groups and a long hydrophobic chain was synthesized, and it showed highly selective recognition of carbenicillin (a typical beta-lactam antibiotic) in 100% aqueous solution via concerted interactions.
An asymmetric 5-endo chloroetherification of homoallylic alcohols is successfully developed that employs an easily available quaternary ammonium salt derived from cinchonine as a conventional organocatalyst. This approach provides ready access to β-chlorotetrahydrofurans in high enantioselectivities.
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