摘要:
The stereochemistry of sialylation of an acceptor saccharide to obtain an .alpha. (2-3) or .alpha. (2-6) linkage is controlled to favor the .alpha. anomer by use of an aromatic ester of the sialyl reagent. The resulting intermediate .alpha. (2-3) and .alpha. (2-6) sialylated intermediate disaccharide blocks are useful in the synthesis of antigenic substances which can be used to raise antibodies useful in diagnosis and therapy, and can themselves be used as reagents in various applications. The preparation of the tetrasaccharide antigens corresponding to the 19-9 and sialyl-X antigens characteristic of malignant tissue illustrates the application of this method.
摘要:
The present invention is directed to a method for producing crude sialic acid, comprising hydrolysis of a delipidated egg yolk and a method for producing high purity sialic acid, which comprises desalting a solution containing sialic acid obtainable by hydrolyzing a delipidated egg yolk, adsorbing sialic acid to an anion exchange resin and then eluting said sialic acid.The present invention makes it possible to produce and purify sialic acid from delipidated egg yolk on an industrial scale.
摘要:
A repairing agent for cells and tissues is disclosed, which agent comprises, as an active ingredient, a compound of the general formula: ##STR1## wherein Z represents lithium, potassium, sodium, ammonium or an organic ammonium when n is 1, and Z represents calcium, barium or magnesium when n is 2.
摘要:
This invention provides a novel compound expressed by the following formula (1): ##STR1## [wherein R.sup.1 denotes a hydrogen atom or CH.sub.3 CO--, R.sup.2 denotes --COOR.sup.4 (R.sup.4 denotes Na or a methyl group) or ##STR2## (R.sup.5 denotes a hydrogen atom, --COC.sub.6 H.sub.5 or --Si(C.sub.6 H.sub.5).sub.2 C(CH.sub.3).sub.3 and R.sup.3 denotes ##STR3## (R.sup.5 denotes a hydrogen atom, --COC.sub.6 H.sub.5 or --Si(C.sub.6 H.sub.5).sub.2 C(CH.sub.3).sub.3) when R.sup.2 is --COOR.sup.4 (R.sup.4 denotes Na or a methyl group) or denotes --COOR.sup.4 when R.sup.2 is ##STR4## and a method of preparation thereof. The above novel compounds of present invention are useful as a tumor maker, a molecular marker for cells having the ability of differential induction, or an intermediate of the synthesis thereof. 'Y
摘要:
The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogulonic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogulonic acid is readily converted to ascorbic acid.
摘要:
Certain 3,5-disubstituted-2,4,6-triiodoanilides of polyhydroxy-monobasic acids are useful as x-ray contrast agents. Representative of this class of compounds is the compound 3-gluconamido-2,4,6-triiodo-N-methyl-5-(N-methyl-acetamido)-benzamide and the compound 3-gluconamido-5-[N-(2-hydroxyethyl)acetamido]-2,4,6-triiodo-N-methylbenzamide.
摘要:
A synthetic route to ascorbic acid is provided in which a 3,5:4,6-protected derivative of gulonic acid is prepared from gulono-1,4-lactone. Oxidation of the derivative and hydrolysis of the resulting product affords 2-ketogulonic acid or ester thereof which can be readily converted to ascorbic acid by known methods.
摘要:
The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogluconic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogluconic acid is readily converted to ascorbic acid.
摘要:
Ascorbic acid is prepared from a 1,4-lactone selected from gulono-1,4-lactone, galactono-1,4-lactone, idono-1,4-lactone and talono-1,4-lactone by a process comprising protection of the hydroxyl groups of the lactone so as to form an intermediate having a free hydroxyl group at either, but not both, the 2- or 3-position, oxidizing this free hydroxyl group to a keto group and hydrolyzing the oxidized intermediate to remove the hydroxyl-protecting groups.
摘要:
2-Keto-L-gulonic acid is prepared from 2,5-diketo-D-gluconic acid through microbial conversion. The 2-keto-L-gulonic acid producing microorganism used for this microbial conversion includes strains which belong to genera of Brevibacterium, Arthrobacter, Micrococcus, Staphylococcus, Pseudomonas and Bacillus. Both the incubation of the microorganism in a medium containing 2,5-diketo-L-gluconic acid and the direct contact of any products obtained from the cells with a substrate containing said 2,5-diketo-D-gluconic acid may be used in the disclosed process.