- Method for simply and conveniently synthesizing tiglic acid
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The invention discloses a method for simply and conveniently synthesizing tiglic acid. The method comprises the following steps: carrying out an addition reaction between a Grignard reagent and pyruvic acid or alpha-butanone acid at a normal temperature by using HMPA or DMPU as an assistant to obtain 2-hydroxy-2-methylbutyric acid, marking the 2-hydroxy-2-methylbutyric acid as an intermediate III;and then, heating the intermediate III under the action of sulfuric acid with a mass concentration of not less than 67% to carry out dehydration reaction to obtain tiglic acid. Materials which can cause serious pollution in the prior art are not used, the reaction steps are short, the technological conditions are simple, no special requirements for equipment exist, the product yield is high, andthe method is suitable for industrial production.
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Paragraph 0017; 0035; 0037-0039
(2020/06/20)
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- A convenient one-pot synthesis of quaternary α-methoxy- and α- hydroxycarboxylic acids
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Several α-methoxy- and α-hydroxycarboxylic acids have been synthesized by a new one-pot synthesis using ketones, tribromomethane, and potassium hydroxide in methanol and water, respectively, in good yields.
- Yabuuchi, Tetsuya,Kusumi, Takenori
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p. 684 - 686
(2007/10/03)
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- Making optically active alpha-hydroxy acids or precursors
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Disclosed is a process for making an α-hydroxy acid which is essentially all L or all D with respect to the chiral C atom bonded to the carboxy group of said acid which comprises (1) hydrocarboxylating an enol acylate, which has a chiral C atom that is essentially all L or all D, with CO and water or an organic hydroxyl compound, thereby producing a reaction mixture containing diastereomeric α-acyloxy acids or esters having two chiral centers and having essentially no enantiomeric pairs, (2) separating the diastereomers by conventional physical means and (3) hydrolyzing at least one of said separated diastereomers to make at least the α-hydroxy acid which is essentially all L or all D with respect to the chiral C atom bonded to the carboxy group of said acid. Also disclosed is a process for making an α-hydroxy acid which is essentially all L or all D with respect to the chiral C atom bonded to the carboxy group of said acid which comprises (1) hydrocarboxylating an enol acylate, the enol portion of which has a chiral C atom that is essentially all L or all D, with CO and water or an organic hydroxyl compound, thereby producing a reaction mixture containing diastereomeric α-acyloxy acids or esters having two chiral centers and having essentially no enantiomeric pairs, (2) hydrolyzing the product of (1) to make a diastereomeric mixture containing α-hydroxy acids, and (3) separating by conventional physical means from the product of (2) at least one α-hydroxy acid which is essentially all L or all D with respect to the chiral C atom bonded to the carboxy group of said acid.
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- Ethers of 1-benzyl-3-hydroxymethyl-indazole with aliphatic 2-hydroxyacids
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Compounds of the formula, A-CH2-O-CRR?-COOR''' (I), wherein A, R, R? and R''' have the meanings mentioned in the description, salts thereof with pharmaceutically acceptable bases, intermediates and processes for their preparation, and pharmaceutical compositions containing them.
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- Method of making a diastereomeric mixture containing two diastereomeric α-acyloxy acid esters
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In the process of hydrocarboxylating an enol acylate with CO and an organic hydroxyl compound to produce an α-acyloxy acid ester, the improvement comprising using as the organic hydroxyl compound reactant, an organic hydroxyl compound which has a chiral center that is essentially all L or D, thereby producing a reaction mixture having essentially no enantiomeric pairs and containing diastereomeric α-acyloxy acid esters having two chiral centers.
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