کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2484271 1114305 2016 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mechanism of Decarboxylation of Pyruvic Acid in the Presence of Hydrogen Peroxide
ترجمه فارسی عنوان
مکانیسم دککاربوسیلیک اسید پریوویک در حضور پراکسید هیدروژن
موضوعات مرتبط
علوم پزشکی و سلامت داروسازی، سم شناسی و علوم دارویی اکتشاف دارویی
چکیده انگلیسی
The purpose of this work was to probe the rate and mechanism of rapid decarboxylation of pyruvic acid in the presence of hydrogen peroxide (H2O2) to acetic acid and carbon dioxide over the pH range 2-9 at 25°C, utilizing UV spectrophotometry, high performance liquid chromatography (HPLC), and proton and carbon nuclear magnetic resonance spectrometry (1H, 13C-NMR). Changes in UV absorbance at 220 nm were used to determine the kinetics as the reaction was too fast to follow by HPLC or NMR in much of the pH range. The rate constants for the reaction were determined in the presence of molar excess of H2O2 resulting in pseudo first-order kinetics. No buffer catalysis was observed. The calculated second-order rate constants for the reaction followed a sigmoidal shape with pH-independent regions below pH 3 and above pH 7 but increased between pH 4 and 6. Between pH 4 and 9, the results were in agreement with a change from rate-determining nucleophilic attack of the deprotonated peroxide species, HOO−, on the α-carbonyl group followed by rapid decarboxylation at pH values below 6 to rate-determining decarboxylation above pH 7. The addition of H2O2 to ethyl pyruvate was also characterized.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Pharmaceutical Sciences - Volume 105, Issue 2, February 2016, Pages 705-713
نویسندگان
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