摘要:
The invention provides an extraction process for the recovery of ascorbic id from an aqueous feed solution containing the acid at a concentration of less than 0.7 mol/kg.
摘要:
A method is provided for producing L-ascorbic acid (Vitamin-C) in a single process step. Starting material, particularly a mixture of compounds from the group consisting of glucose, sorbitol, sorbose, and 2-keto-L-gulonic acid, is catalytically oxidized in aqueous solution by hypochlorous acid. L-ascorbic acid then can be separated from the aqueous solution, and the unconverted reactants recycled for greater conversion. The reaction occurs in the aqueous state at ambient temperature near a pH of 5.5 when an optimum amount of hydrous cobalt-oxide is present in the solution.
摘要:
L-ascorbic acid is produced by allowing an acid to act on 2-keto-L-gulonic acid in a mixture solvent of an inert organic solvent and an aliphatic ketone in the presence of water and a surfactant.The method produces L-ascorbic acid in a high yield 90% or more and is an industrially advantageous method.
摘要:
A process for the preparation of ascorbic acid starting from an ascorbate is characterized in that an ascorbate, e.g. sodium ascorbate, dissolved in water is decomposed under the influence of an electric field by means of ion-selective membranes into ascorbate ions and cations and the latter are separated spatially from one another and then, as a result of simultaneous generation of protons and hydroxide ions, the ascorbic acid is prepared from the liberated ascorbate ions and protons and, spatially separated therefrom, the corresponding hydroxide, e.g. sodium hydroxide, is also prepared from the cations and hydroxide ions.
摘要:
The present invention relates to a method for synthesis of optically pure stereogenically labile 4-aryl-2-hydroxytetronic acids from an optically pure aidehyde. The invention further relates to the use of such optically pure compounds as potent inhibitors of platelet aggregation by working at the level of cyclooxygenase, and additionally as inhibitors of cyclooxygenase and 5-lipoxygenase. The invention further relates to the pharmaceutical use of such.compounds in the treatment of coronary artery diseases, especially in the treatment and/or prevention of atherosclerosis, and in the treatment of various inflammatory pathologies, especially arthritis.
摘要:
A class of cysteine protease inhibitors which inactivate a cysteine protease by covalently bonding to the protease and releasing a heterocyclic leaving group is presented. The cysteine protease inhibitors of the present invention comprise a first portion which targets a desired cysteine protease and positions the inhibitor near the thiolate anion portion of the active site of the protease, and a second portion which covalently bonds to the cysteine protease and irreversibly deactivates that protease by providing a carbonyl or carbonyl-equivalent which is attacked by the thiolate anion of the active site of the cysteine protease to sequentially cleave a heterocyclic leaving group. The heterocyclic leaving group of the protease inhibitor is of the formula: --O-- Het, where Het is a heterocycle having 4-7 atoms in the ring, with at least one of the heterocycle atoms being N, O or S.
摘要:
Process for preparing pure ascorbic acid from 2-keto-L-gulonic acid or its sodium salt, by carrying out the following successive steps:esterification of 2-keto-L-gulonic acid or its sodium saltlactonization to sodium ascorbateoptional separation of the sodium ascorbatedisplacement of the ascorbic acid from its saltseparation of the sodium sulphateseparation and purification of the ascorbic acid from its methanolic or aqueous-methanolic solution.
摘要:
This invention relates to 4-phenoxy (and 4-substituted phenoxy)5-hydroxy-2(5H)-furanones of the formula: ##STR1## where Z is ##STR2## where R is H, halogen, C.sub.1 -C.sub.8 alkyl, C.sub.3 -C.sub.8 cycloalkyl, trifluoromethyl, or ##STR3## and X is H, C.sub.1 -C.sub.8 alkyl, --O--C.sub.1 -C.sub.8 alkyl, or halogen; a process for their preparation, their use in the treatment of osteoporosis, and pharmaceutical compositions thereof.
摘要:
The present invention relates to a method for synthesis of optically pure stereogenically labile 4-substituted-2-hydroxytetronic acids from an asymmetric .alpha.-hydroxy ester. The chiron approach of the present invention utilizes a non-nucleophilic lithium amide base under kinetically controlled Claisen conditions to produce a 4-substituted-2-pheylmethoxy precursor to the 4-substituted-2-hydroxy tetronic acid. The invention further relates to the use of such optically pure compounds as potent inhibitors of platelet aggregation by working at the level of cyclooxygenase. The invention further relates to the pharmaceutical use of such compounds in the treatment of coronary artery diseases, especially in the treatment and/or prevention of atherosclerosis.
摘要:
This invention relates to a novel ascorbic acid derivative having excellent antioxidant action and a process for preparing the same.Furthermore, this invention also relates to a novel antioxidant comprising the aforementioned ascorbic acid derivative or other known ascorbic acid derivatives.