نتایج جستجو برای: trimethylsilylation
تعداد نتایج: 65 فیلتر نتایج به سال:
trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (hmds) in solution and under solvent-free conditions is reported. trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. in addition, sio2-cl can be recovered and reused after drying.
As an attempt to elucidate the factor(s) responsible for the poor performance of a copper(II)-phthalocyanine aminopropylsilica gels (CU-PCSD) column for HPLC, the silanol and/or amino groups remaining on Cu-PCSD were endcapped with trimethylchlorosilane (TMCS) or N-trimethylsilylimidazole (TMSI). The trimethylsilylated Cu-PCS(D)S (Cu-PCSD-TMCS and -TMSI) were investigated concerning their perfo...
A gas-chromatographic method for urinary organic acid analysis is described, designed to be used routinely for the diagnosis of organic aciduria. It involves extraction of urine with ethyl acetate, dehydration of extract residues, and trimethylsilylation. Organic acids are identified by using an extensive list of retention indices published in the accompanying paper (this issue). Quantitative v...
Trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (HMDS) in solution and under solvent-free conditions is reported. Trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. In addition, SiO2-Cl can be recovered and reused after drying.
This report discloses a mild and efficient O-acetylation using easily accessible TMSOAc as novel acetyl reagent O-trimethylsilylation HMDS for various alcohols catalyzed by tunable Brønsted acidic ionic liquids (TBAILs). Imidazolium-based TBAILs were prepared two-step atom-economic reaction acidities measured UV-visible spectroscopy. Both protections accomplished at room temperature with good t...
The specificity of a GC/MS assay of morphine and codeine was examined with particular regard to the potential interference due to hydromorphone and hydrocodone, compounds that cross-react extensively in opiate screening tests. A GC/MS method with solid-phase extraction and acetylation or trimethylsilylation was used. The equilibrium between keto and enol forms of the potential interferents was ...
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