- A D - (-) - pantoic acid lactone synthesis method
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The invention discloses a vitamin B5 synthesis of key intermediate D - (-) - pantoic acid lactone synthetic method, using (R)- (+) - α - phenethylamine hydrochloride or sulfate as a chiral reagent with a racemic pantoic acid alkali metal salt reaction, filtering to remove the inorganic salt, the mother liquor is concentrated to get pantoic acid - (R)- phenethylamine diastereomers salt, by the re-crystallization or beating of the diastereoisomer of the double salt method to carry out the purification, filtering to obtain (D)- pantoic acid - (R)- phenethylamine salt, and (L)- pantoic acid - (R)- phenethylamine salt is dissolved in the solvent, (D)- pantoic acid - (R)- phenethylamine salt and then subjected to a decomposition, acidified cyclization to obtain D - (-) - pantoic acid lactone.
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Paragraph 0029
(2019/03/24)
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- Synthetic method of D,L-pantolactone
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The invention belongs to the field of chemical technology, and more specifically relates to a synthetic method of D,L-pantolactone. The synthetic method of D,L-pantolactone comprises following steps:paraformaldehyde and isobutyraldehyde are subjected to aldol condensation reaction under the effect of an alcohol solvent and an alkaline catalyst, and an obtained reaction solution is directly used in a next step treatment without separation; hydrocyanic acid is added, reaction is carried out to generate 2, 4-dihydroxyl-3, 3-dimethylbutyronitrile; 2, 4-dihydroxyl-3, 3-dimethylbutyronitrile is subjected to esterification reaction under acidic conditions to obtain 2, 4-dihydroxyl-3, 3-dimethyl butyrate; an alkali is added for neutralizing of excess acid, and solid liquid separation is carried out to obtain a side product ammonium salt; liquid evaporation is carried out for alcohol recycling, and rectification is carried out to obtain D,L-pantolactone product. The synthetic method of D,L-pantolactone is capable of preparing a target product high in content and yield, reducing acid and alkali using amount, avoiding using of organic solvents in production extraction, reducing generated waste water greatly, saving energy, protecting the environment, and reducing cost.
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Paragraph 0056; 0059-0060; 0061; 0064-0065; 0066; 0069-0070
(2019/12/09)
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- R-HNL random variants and their use for preparing optically pure, sterically hindered cyanohydrins
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The invention relates to R -hydroxynitrile lyases with improved substrate acceptance, increased activity and increased selectivity, obtainable by introducing random mutations with the aid of random mutagenesis and/or saturation mutagenesis techniques, ide
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Paragraph 0189-0191
(2015/12/18)
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- Nitrile hydratase and a method for producing amides
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An objective of the present invention is to provide a nitrile hydratase capable of producing 2-hydroxy-4-methylthiobutyroamide. The present invention provides a novel nitrile hydratase producing α-hydroxyamide using, α-hydroxnitrile as the substrate, and the encoding DNA thereof. The enzyme can be obtained from Rhodococcus sp. Further, the enzymatic activity of the enzyme can he maintained stably during the reaction. The present invention provides a method for producing amide compounds, the method comprising the step of reacting this enzyme to nitrile compounds. According to the present invention, from hydroxy nitrile compounds, corresponding amide compounds can be produced biochemically without reducing the enzyme activity of nitrile hydratase.
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- A convenient dehydration procedure for the synthesis of enantiomerically pure cyanohydrins
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Starting from protected α-hydroxy amides; cyanohydrins (α-hydroxy nitriles) are obtained through dehydration by cyanuric chloride/DMF in excellent yield. The advantages of the procedure are the extremely mild reaction conditions that prevent racemization.
- Aquino, Fabrice,Pauling, Horst,Walther, Willy,Plattner, Dietmar A.,Bonrath, Werner
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p. 731 - 737
(2007/10/03)
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