- Method for preparing L-selenomethionine
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The invention discloses a method for preparing L-selenomethionine and belongs to the field of additives. The method comprises the following steps: A. subjecting L-methionine and iodomethane to a reaction in water, so as to obtain an intermediate; and B. subjecting the intermediate and selenium sodium methoxide to a reaction in an alcoholic solvent, carrying out quenching with glacial acetic acid after the reaction ends up, adjusting a pH value of a reaction system to 5 to 6, and carrying out filtering and baking, thereby obtaining the L-selenomethionine. The method has the beneficial technicaleffects that the intermediate is simpler in preparation and lower in cost; the preparation operation of the intermediate is simpler; and employed raw materials and reagents are commercially available, a reaction process is free of production of fetid and hypertoxic byproduct, and thus, the method is more beneficial to labor protection and environments.
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Paragraph 0011; 0016-0030
(2020/02/17)
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- Synthetic method of L-selenomethionine
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The invention discloses a synthetic method of L-selenomethionine, and belongs to the field of additives. The synthetic method comprises the following steps: A, a compound 1 and a compound 2 react in asolvent, and filtering and drying are carried out after a reaction is completed, and then a green solid compound 3 is obtained; and B, the compound 3 and sodium borohydride react in a protonic solvent for 1-10 h, after a reaction is completed, dimethyl sulfate is dropwise added to continue to react for 1-5 h, then quenching through acetic acid and filtering are conducted, and thus the L-selenomethionine is prepared. The synthetic method has the beneficial effects that 1, it is reported in the literature that the compound 1 is mild in condition and high in yield; 2, the compound 2 is mild in reaction condition, no highly toxic and foul sodium methyl selenide is generated, and labor protection and environmental protection are facilitated; 3, the compound 2 is easy to separate only through centrifugal spinning-filtration, and an obtained product is high in purity; and 4, adopted raw materials and reagents are all commercially available, in the preparation process of the L-selenomethionine, intermediates do not need to be separated, and operation is easy.
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Paragraph 0026-0039
(2020/02/17)
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- Preparation method of L-selenomethionine
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The invention discloses a preparation method of L-selenomethionine, and belongs to the field of additives. The preparation method comprises the following steps of A. reacting a compound 1 with a compound 2 in a solvent, and filtering after reaction to obtain a green solid compound 3; B. firstly, reacting the compound 3 with sodium borohydride in a protic solvent for 1-10 hours, dripping dimethyl sulfate after the reaction time is reached, continuing to react for 1-5 hours, quenching by using acetic acid, filtering and drying to obtain the L-selenomethionine. The preparation method disclosed bythe invention has the beneficial effects that: 1. the compound 1 has mild condition and high yield; 2. the reaction condition of the compound 3 is mild, virulent and malodorous selenium sodium methoxide cannot be generated, and the labor protection and the environmental protection are facilitated; 3. the compound 3 is simple to separate and only needs to be centrifugally subjected to spin filtration, and the obtained product has high purity; and 4. the raw materials and reagents are commercially available, and the intermediate does not need to be separated in the preparation process of the L-selenomethionine, so that the operation is simple.
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Paragraph 0030-0040
(2020/01/12)
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- Method for synthesizing L L-(+)-selenomethionine (by machine translation)
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The synthetic route disclosed L - (+) - by the invention has, L - (+) - the advantages that the raw materials, are easy to obtain, the reaction conditions are, mild, the reaction conditions are mild, the separation, and purification are easy, L - (+) - and the; method L - (+) - is easy, to separate and purify L - (+) - L - (+) - L - (+) . (by machine translation)
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Paragraph 0041; 0050-0052; 0058-0062; 0069-0071; 0078-0080
(2019/12/25)
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- Method for synthesizing selenomethionine by adopting one-pot method
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The invention discloses a method for synthesizing selenomethionine by adopting a one-pot method. The method comprises the following steps: mixing selenium and a reducing agent and performing a reducing reaction to obtain metal dioxide M-2Se2; adding alpha-amino protected homoserine lactones in a solution containing metal dioxide M-2Se2 and generated when the reducing reaction is finished to perform a reaction to obtain alpha-amino protected homocysteine diselenide; and reducing the alpha-amino protected homocysteine diselenide, and then performing methylation to obtain alpha-amino protected selenomethionine; and performing deprotection on the alpha-amino protected selenomethionine to obtain selenomethionine. Through the adoption of the way, the method is low in cost, high in yield and highin product purity, can be used for large batch production, avoids toxicity pollution possibly generated in the process link, and greatly reduces environmental pollution and injury to operation personnel.
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Paragraph 0020
(2018/12/05)
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- Preparation method of high-optical-purity D- or L-selenomethionine
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The invention discloses a preparation method of high-optical-purity D- or L-selenomethionine. The preparation method comprises the following steps: by taking D- or L-methionine as initial raw materials and diethyl sulfate or halogenated alkyl acid or derived esters as alkylation reagents, generating sulfonium salt, desulfurizing and closing ring under acidic conditions, to produce alpha-amino-gama-butyrolactone halate, having addition reaction to alpha-amino-gama-butyrolactone halate with methyl selenol salt and opening ring, acidifying with organic acid, and recrystallizing to obtain D- or L-selenomethionine. The chemical purity of the product is more than or equal to 99%, and the high optical purity is more than or equal to 99%. The preparation method is low-cost and easily available in raw materials, simple in steps and easy to operate, simple in reaction conditions, and suitable for large-scale production.
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Paragraph 0028; 0030
(2017/08/30)
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- Peptide Tyrosinase Activators
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Peptides that increase melanin synthesis are provided. These peptides include pentapeptides YSSWY, YRSRK, and their variants. The peptides may activate the enzymatic activity of tyrosinase to increase melanin synthesis. The pharmaceutical, cosmetic, and other compositions including the peptides are also provided. The methods of increasing melanin production in epidermis of a subject are provided where the methods include administering compositions comprising an amount of one or more peptides effective to increase the melanin production. The methods also include treating vitiligo or other hypopigmentation disorders with compositions including one or more peptides.
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- Synthesis and biological evaluation of novel curcuminoid derivatives
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Curcuminoids have been reported to possess multiple bioactivities, such as antioxidant, anticancer and anti-inflammatory properties. Three novel series of curcuminoid derivatives (11a-h, 15a-h and 19a-d) with enhanced bioactivity have been synthesized. Among the synthesized compounds, 11b exhibited the most significant activity with an MIC of 0.5 μ M /mL against selected medically important Gram-positive cocci (S aureus and S viridans) and Gram-negative bacilli (E. coli and E. cloacae). The derivatives exhibited remarkable results in an antioxidant test with an IC50 2.4- to 9.3-folder smaller than curcuminoids. With respect to antiproliferative activity against Hep-G2, LX-2, SMMC7221 and MDA-MB-231, the derivatives exhibited an effect stronger than curcuminoids with an IC50 ranging from 0.18 to 4.25 μ M.
- Cao, Ya-Kun,Li, Hui-Jing,Song, Zhi-Fang,Li, Yang,Huai, Qi-Yong
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p. 16349 - 16372
(2015/01/08)
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- L-selenohomocysteine: One-step synthesis from L-selenomethionine and kinetic analysis as substrate for methionine synthases
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A single-step convenient synthesis of L-selenohomocysteine (SeHcy) from L-selenomethionine (SeMet) using sodium in liquid ammonia is described. Methionine synthases convert SeHcy to SeMet at rates comparable to their rates of conversion of L-homocysteine (Hcy) to L-methionine (Met). This study suggests that SeHcy generated from SeMet metabolism can be efficiently recycled to SeMet in mammals. (C) 2000 Elsevier Science Ltd.
- Zhou, Zhaohui S.,Smith, April E.,Matthews, Rowena G.
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p. 2471 - 2475
(2007/10/03)
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- Acylase I-catalyzed deacetylation of N-acetyl-L-cysteine and S-alkyl-N- acetyl-L-cysteines
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The aminoacylase that catalyzes the hydrolysis of N-acetyl-L-cysteine (NAC) was identified as acylase I after purification by column chromatography and electrophoretic analysis. Rat kidney cytosol was fractionated by ammonium sulfate precipitation, and the proteins were separated by ion-exchange column chromatography, gel-filtration column chromatography, and hydrophobic interaction column chromatography. Acylase activity with NAC and N-acetyl-L- methionine (NAM), a known substrate for acylase I, as substrates coeluted during all chromatographic steps. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the protein was purified to near homogeneity and had a subunit M(r) of 43 000, which is identical with the M(r) of acylase I from porcine kidney and bovine liver. n-Butylmalonic acid was a slow-binding inhibitor of acylase I and inhibited the deacetylation of NAC with a K(i) of 192 ± 27 μM. These results show that acylase I catalyzes the deacetylation of NAC. The acylase I-catalyzed deacetylation of a range of S-alkyl-N- acetyl-L-cysteines, their carbon and oxygen analogues, and the selenium analogue of NAM was also studied with porcine kidney acylase I. The specific activity of the acylase I-catalyzed deacetylation of these substrates was related to their calculated molar volumes and log P values. The S-alkyl-N- acetyl-L-cysteines with short (C0-C3) and unbranched S-alkyl substituents were good acylase I substrates, whereas the S-alkyl-N-acetyl-L-cysteines with long (>C3) and branched S-alkyl substituents were poor acylase I substrates. The carbon and oxygen analogues of S-methyl-N-acetyl-L-cysteine and the carbon analogue of S-ethyl-N-acetyl-L-cysteine were poor acylase I substrates, whereas the selenium analogue of NAM was a good acylase I substrate.
- Uttamsing, Vinita,Keller,Anders
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p. 800 - 809
(2007/10/03)
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- L-Methionine related 1-amino acids by acylase cleavage of their corresponding N-acetyl-DL-derivatives
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Acylase I from Aspergillus oryzae is an even more useful enzyme than suggested so far. Besides standard amino acids such as L-Met, L-Val and L-Phe, a number of additional sulfur- and selenium-containing amino acids can be obtained at useful reaction rates and in very high enantiomeric purity by kinetic resolution of the respective N-acetyl-DL-amino acids.
- Bommarius, Andreas S.,Drauz, Karlheinz,Guenther, Kurt,Knaup, Guenter,Schwarm, Michael
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p. 3197 - 3200
(2007/10/03)
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- EFFICIENT SYNTHESES OF (d,l) AND (d) SELENOMETHIONINE
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Selenomethionine or its protected forms have been prepared from methylselenolates and α-functionalized γ-butyrolactones or α-functionalized methyl cyclopropane carboxylates.
- Krief, A.,Trabelsi, M.
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p. 1203 - 1210
(2007/10/02)
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- CONCISE SYNTHESES OF L-SELENOMETHIONINE AND OF L-SELENOCYSTINE USING RADICAL CHAIN REACTIONS
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L-Selenomethionine and L-selenocystine were prepared in high overall yields from protected L-glutamic and L-aspartic acid derivatives respectively.Irradiation of the mixed anhydrides (esters) derived from 4 (e.g. 15) in the presence of dimethyldiselenide provided the protected L-selenomethionine 16 directly.We have shown that triselenocyanide Se3(CN)2 can serve as an efficient selenocyanating agent for radicals; the selenocyanide group is a good precursor for the diselenide moiety of L-selenocystine.
- Barton, Derek H. R.,Bridon, Dominique,Herve, Yolande,Potier, Pierre,Thierry, Josiane,Zard, Samir Z.
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p. 4983 - 4990
(2007/10/02)
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