Glucose is a Precursor of 1-deoxynojirimycin and 1-deoxymannonojirimycin in Streptomyces subrutilus
摘要:
Streptomyces subrutilus ATCC 27467, when grown on a glucose-containing soyabean medium, produces both 1-deoxymannonojirimycin (DMJ) and 1-deoxynojirimycin (DNJ) in its culture medium. When 1- or 2-[H-2]-D-glucose is used, the deuterium label appears at C6 in both alkaloids and the labelling pattern suggests that the first step in the biosynthesis of both DNJ and DMJ is a glucose to fructose isomerisation. Studies with 5-[H-2]- and 6,6-[H-2(2)]-D-glucose indicate that oxidation of the 6-position of the glucose/fructose occurs during the biosynthesis and that mannonojirimycin is the first aminosugar to be formed. Mannonojirimycin can then undergo dehydration and reduction to DMJ. Alternatively, epimerisation of mannonojirimycin can occur at C2 to give norjirimycin which is then dehydrated and reduced to DNJ.
CATALYTIC CONVERSION OF CELLULOSE TO FUELS AND CHEMICALS USING BORONIC ACIDS
申请人:Raines Ronald
公开号:US20130178617A1
公开(公告)日:2013-07-11
Methods and catalyst compositions for formation of furans from carbohydrates. A carbohydrate substrate is heating in the presence of a 2-substituted phenylboronic acid (or salt or hydrate thereof) and optionally a magnesium or calcium halide salt. The reaction is carried out in a polar aprotic solvent other than an ionic liquid, an ionic liquid or a mixture thereof. Additional of a selected amount of water to the reaction can enhance the yield of furans.
The present invention is directed to methods for preparing sorbose from glucose, said method comprising: (a) contacting the glucose with a silica-containing structure comprising a zeolite having a topology of a 12 membered-ring or larger, an ordered mesoporous silica material, or an amorphous silica, said structure containing Lewis acidic Ti
4+
or Zr
4+
or both Ti
4+
and Zr
4+
framework centers, said contacting conducted under reaction conditions sufficient to isomerize the glucose to sorbose. The sorbose may be (b) separated or isolated; or (c) converted to ascorbic acid.
Titanium-Beta Zeolites Catalyze the Stereospecific Isomerization of <scp>d</scp>-Glucose to <scp>l</scp>-Sorbose via Intramolecular C5–C1 Hydride Shift
作者:Rajamani Gounder、Mark E. Davis
DOI:10.1021/cs400273c
日期:2013.7.5
Pure-silica zeolite beta containing Lewis acidic framework Ti4+ centers (Ti-Beta) is shown to catalyze the isomerization of d-glucose to l-sorbose via an intramolecular C5–C1 hydride shift. Glucose–sorbose isomerization occurs in parallel to glucose–fructose isomerization on Ti-Beta in both water and methanol solvents, with fructose formed as the predominant product in water and sorbose as the predominant
[EN] CATALYTIC CONVERSION OF CELLULOSE TO FUELS AND CHEMICALS USING BORONIC ACIDS<br/>[FR] CONVERSION CATALYTIQUE DE LA CELLULOSE EN CARBURANTS ET EN PRODUITS CHIMIQUES AVEC DES ACIDES BORONIQUES
申请人:WISCONSIN ALUMNI RES FOUND
公开号:WO2013049424A1
公开(公告)日:2013-04-04
Methods and catalyst compositions for formation of furans from carbohydrates. A carbohydrate substrate is heating in the presence of a 2-substituted phenylboronic acid (or salt or hydrate thereof) and optionally a magnesium or calcium halide salt. The reaction is carried out in a polar aprotic solvent other than an ionic liquid, an ionic liquid or a mixture thereof. Additional of a selected amount of water to the reaction can enhance the yield of furans.