149-87-1Relevant articles and documents
Degradation kinetics of L-glutamine in aqueous solution
Arii, Kanji,Kobayashi, Hideyuki,Kai, Toshiya,Kokuba, Yukifumi
, p. 75 - 78 (1999)
The degradation kinetics of L-glutamine (Gln) in aqueous solution was studied as a function of buffer concentration, pH and temperature. Stability tests were performed using a stability-indicating high-performance liquid chromatographic assay. The degradation product of Gln was 5-pyrrolidone-2-carboxylic acid. The reaction order for Gln in aqueous solution followed pseudo-first-order kinetics under all experimental conditions. The maximum stability of Gln was observed in the pH range from 5.0 to 7.5. The pH-rate profile described by specific acid-base catalysis and hydrolysis by water molecules agreed with the experimental results. Arrhenius plots showed the temperature dependence of Gln degradation, and the apparent activation energy at pH 6.41 was determined to be 9.87x104 J mol-1. Copyright (C) 1999 Elsevier Science B.V.
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Adler et al.
, p. 90,92 (1963)
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Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
Yakukhnov, Sergey A.,Ananikov, Valentine P.
supporting information, p. 4781 - 4789 (2019/09/16)
A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
Synthetic method of Boc-L-Pyroglutamic acid methyl ester
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Paragraph 0038; 0039; 0040, (2017/05/23)
The invention discloses a synthetic method of Boc-L-Pyroglutamic acid methyl ester. The synthetic method comprises the following steps: dissolving L-pyroglutamic acid into methanol, adding a catalyst thionyl chloride and reacting, adding sodium bicarbonate to stop the reaction and generating methyl L-pyroglutamate; dissolving Methyl L-pyroglutamate into dichloromethane, adding a catalyst DMAP, adding di-tert-butyl dicarbonate in batches, and reacting to generate Boc-L-Pyroglutamic acid methyl ester. By using L-pyroglutamic acid as a raw material for preparation of Boc-L-Pyroglutamic acid methyl ester, the method has advantages of simple operation and low cost. The Boc-L-Pyroglutamic acid methyl ester prepared by the method has high yield, and purity can reach 99.8%. The product can meet quality requirements of the market. Therefore, the method is simple to operate, is convenient to prepare, is low-cost, is green and environment friendly, has no harsh reaction condition, and is suitable for large-scale industrial production.
A L-villaggio glu preparation method (by machine translation)
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Paragraph 0026-0027; 0032; 0039, (2017/04/11)
The invention discloses a preparation method of an L-pyroglutamic acid. The preparation method comprises the following steps: 1, melting, namely melting a L-glutamic acid serving as a raw material at a temperature ranging from 170 DEG C to 180 DEG C and under the pressure ranging from 0.45MP to 0.55MP; 2, cooling, namely after the temperature of the melt falls, feeding the melt into a cooling tank until the melt is completely coagulated into a block; 3, decoloring, namely putting the cooled block into mother liquor, increasing the temperature to the range of 70 DEG C to 75 DEG C and then adding activated carbon for decoloring; 4, filtering, namely filtering by use of a plate frame and remaining the filtrate for crystallization; 5, cooling the filtrate and separating out crystals; and 6, separating, namely putting the solid-liquid mixture after crystallization into a centrifugal separator to separate out the finished product L-pyroglutamic acid. Due to the adopted technical scheme of the preparation method of the L-pyroglutamic acid, the reaction temperature is reduced, and DL-pyroglutamic acid and other impurities are reduced; the production efficiency is improved; the production steps are reduced so that the cost is reduced; the quality and yield of the product are obviously improved and increased, and large-scale production can be realized.
