- Preparation process of ascorbyl ethyl ether
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The invention relates to a preparation process of ascorbyl ethyl ether. The preparation process comprises the following steps: with ascorbic acid and acetone as raw materials, carrying out reacting for 8-10 hours under the catalysis of oxalyl chloride, and then carrying out filtering, washing and drying to obtain 5,6-O-isopropylidene-L-ascorbic acid; adding alkaline-earth metal oxide into mother liquor to remove oxalic acid, hydrogen chloride and moisture, and drying acetone with a molecular sieve for reuse; dissolving an ethylation reagent, inorganic base and 5,6-O-isopropyl-L-ascorbic acid in ethanol, carrying out reacting for 6-8 hours at 40-60 DEG C, and carrying out purifying to obtain 3-ethyl-5,6-O-isopropyl-L-ascorbic acid; removing isopropyl protecting groups through an alcohol solution of hydrogen chloride, carrying out concentrating, adding a solvent with low solubility, and conducting recrystallizing to obtain the ascorbyl ethyl ether. The process solves problems in recoveryand reuse of acetone, does not use toxic and harmful solvents and organic alkali, does not produce a large amount of waste liquid, and is economic and environment-friendly; technological process is easy to control; and the process is high in yield and easy to industrially popularize.
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Paragraph 0061-0064
(2020/08/30)
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- One-Pot 2-o-alkylation of l -ascorbic acid
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One-pot 2-O-alkylation of l-ascorbic acid involving an in situ 3-O-silylation and desilylation sequence was investigated. Initially the 3-OH group was masked with a t-butyldimethylsilyl (TBDMS) group followed by alkylation of the 2-OH group. Removal of the TBDMS group using 20% sulfuric acid also resulted in hydrolysis of the 5,6-O-isopropylidene to give 2-O-alkyl derivatives of l-ascorbic acid. Selective removal of the 3-O-TBDMS with tetrabutylammonium fluoride (TBAF) gave 5,6-O-isopropylidene-2-O-alkyl derivatives of l-ascorbic acid in good overall yields. Through the application of this protocol, 5,6-O-isopropylidene 2-O-alkyl derivatives of l-ascorbic acid as well as 2-O-alkyl derivatives of l-ascorbic acid may be easily accessed. Georg Thieme Verlag Stuttgart · New York.
- Thopate, Shankarr.,Dengale, Rohita.,Kulkarni, Mukundg.
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supporting information
p. 1555 - 1557
(2013/08/23)
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- ASCORBIC ACID DERIVATIVES HAVING ALPHA-LIPOYL GROUPS AND PROCESS FOR PREPARING THE SAME
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The present invention provides an ascorbic acid derivative having an α-lipoyl group and a process for preparing the same. The ascorbic acid derivative of the present invention has excellent stability in an aqueous medium, and thus can minimize denaturation caused by environmental factors such as temperature, light, oxygen, and water, even when being stored in an aqueous composition for a long eriod of time.
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Page/Page column 20-21
(2009/03/07)
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