New Route to Branched-chain Aminodeoxy Sugars by Reaction of Ketoses with Acetonitrile. Synthesis of Methyl 3-C-2′-Aminoethyl-2-deoxy-α-D-arabino-hexopyranoside

1974 ◽  
Vol 52 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Alex Rosenthal ◽  
G. Schöllnhammer
Keyword(s):  
Catalytic Hydrogenation ◽  
Liquid Ammonia ◽  
High Yield ◽  
Lithium Amide ◽  
Branched Chain

Addition of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) to acetonitrile in liquid ammonia at −50 to −60° in the presence of lithium amide gave, in high yield, crystalline methyl 4,6-O-benzylidene-3-C-cyanomethyl-2-deoxy-α-D-arabino-hexopyranoside (2) exclusively. The proof of structure 2 is described. Debenzylidenation of 2 afforded the branched-chain cyano glycoside 3. Compound 3 was converted into its 3,4,6-tri-O-acetate (8) and 4,6-di-O-p-nitrobenzoate (9) derivatives. Catalytic hydrogenation of 3 over rhodium on alumina yielded methyl 3-C-2′-aminoethyl-2-deoxy-α-D-arabino-hexopyranoside which was characterized as its N-2,4-dinitrophenyl derivative (7).

Aryne Chemistry of Podocarpic Acid Derivatives

1994 ◽  
Vol 47 (8) ◽  
pp. 1483 ◽  
Author(s):  
RC Cambie ◽  
PI Higgs ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Anthranilic Acid ◽  
Liquid Ammonia ◽  
Oxidative Cleavage ◽  
High Yield ◽  
Amino Compound ◽  
Bromo Compound

The anthranilic acid (2), a key intermediate for the generation of an aryne at C13 of podocarpic acid derivatives, was synthesized from the 14-amino compound (5) which in turn was generated regiospecifically in high yield by treatment of the 13-bromo compound (25) with sodamide in liquid ammonia. The amine was converted into the anthranilic acid by two separate routes: firstly by directed lithiation and trapping of the lithium species with a CO2 moiety, and secondly by oxidative cleavage of an isatin fused across positions 13 and 14.

scholarly journals Metabolomic analysis of biosynthesis mechanism of ε-polylysine produced by Streptomyces diastatochromogenes

2020 ◽  
Author(s):  
Ziyuan Wang ◽  
Fengzhu Guo ◽  
Tianyu Dong ◽  
Zhilei Tan ◽  
Mohamed Abdelraof ◽  
...  
Keyword(s):  
Metabolic Regulation ◽  
Absorption Capacity ◽  
High Yield ◽  
Regulation Mechanism ◽  
Original Strain ◽  
Metabolomic Analysis ◽  
Streptomyces Sp ◽  
Activity Of Enzymes ◽  
The Difference ◽  
Branched Chain

Abstract ε-polylysine (ε-PL) is a polypeptide that shows broad-spectrum inhibition against both Gram-positive and Gram-negative bacteria, and it’s mainly produced by Streptomyces sp. However, the biosynthesis mechanism of ε-PL by Streptomyces sp. is still unclear. Herein, the metabolomic analysis of the biosynthesis mechanism of ε-PL in the original strain TUST and the high-yield mutant strain 6#-7 were investigated. Results show that the difference on metabolisms between TUST and 6#-7 was significant during fermentation periods. And based on further analyses of the results of both metabolomics and enzymatic activity, a possible metabolic regulation mechanism of the high-yield mutagenized strain 6#-7 was proposed. The transport and absorption capacity for glucose of strain 6#-7 is improved. And the activity of enzymes relating to ε-PL synthesis, including Hexokinase (HK) et al., is strengthened. On the contrary, the activity of enzymes in the branched-chain pathways, such as Succinate dehydrogenase (SDH) et al. is decreased. Meanwhile, the increase of trehalose, glutamic acid and proline makes the strain 6#-7 more resistant to ε-PL. Moreover, the strain 6#-7 has stronger ability to transfer ε-PL out the cell. Thus the ability of the mutagenized strain to synthesize ε-PL is enhanced and the strain 6#-7 can produce more ε-PL compared with the original strain. These findings provide a theoretical basis for further improving the production of ε-PL.

Isopropylidenation of L-arabinose N,N-dimethylhydrazone

1985 ◽  
Vol 50 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Miroslav Koóš ◽  
Harry S. Mosher
Keyword(s):  
Sulfuric Acid ◽  
High Yield ◽  
Cannizzaro Reaction ◽  
Branched Chain

Direct isopropylidenation of L-arabinose N,N-dimethylhydrazone (I) was studied. Four major products whose structures were proven were produced in varying ratios depending upon the conditions. 2,2-Dimethoxypropane and sulfuric acid at 20 °C gave a 36% yield of 2,3:4,5-di-O-isopropylidene-L-arabinose N,N-dimethylhydrazone (II). Attempted aldol condensations directly on this hydrazone with paraformaldehyde were unsuccessful. This hydrazone was readily hydrolyzed to the corresponding protected aldehyde VI which underwent an aldol-Cannizzaro reaction to give the branched chain pentitol VII in high yield.

scholarly journals Metabolomic Analysis of Biosynthesis Mechanism of ε-Polylysine Produced by Streptomyces diastatochromogenes

2021 ◽  
Vol 9 ◽  
Author(s):  
Ziyuan Wang ◽  
Fengzhu Guo ◽  
Tianyu Dong ◽  
Zhilei Tan ◽  
Mohamed Abdelraof ◽  
...  
Keyword(s):  
Metabolic Regulation ◽  
Absorption Capacity ◽  
High Yield ◽  
Regulation Mechanism ◽  
Original Strain ◽  
Metabolomic Analysis ◽  
Homoserine Dehydrogenase ◽  
Yield Strain ◽  
The Difference ◽  
Branched Chain

ε-Polylysine (ε-PL), a natural preservative with broad-spectrum antimicrobial activity, has been widely used as a green food additive, and it is now mainly produced by Streptomyces in industry. In the previous study, strain 6#-7 of high-yield ε-PL was obtained from the original strain TUST by mutagenesis. However, the biosynthesis mechanism of ε-PL in 6#-7 is still unclear. In this study, the metabolomic analyses of the biosynthesis mechanism of ε-PL in both strains are investigated. Results show that the difference in metabolisms between TUST and 6#-7 is significant. Based on the results of both metabolomic and enzymatic activities, a metabolic regulation mechanism of the high-yield strain is revealed. The transport and absorption capacity for glucose of 6#-7 is improved. The enzymatic activity benefits ε-PL synthesis, such as pyruvate kinase and aspartokinase, is strengthened. On the contrary, the activity of homoserine dehydrogenase in the branched-chain pathways is decreased. Meanwhile, the increase of trehalose, glutamic acid, etc. makes 6#-7 more resistant to ε-PL. Thus, the ability of the mutagenized strain 6#-7 to synthesize ε-PL is enhanced, and it can produce more ε-PLs compared with the original strain. For the first time, the metabolomic analysis of the biosynthesis mechanism of ε-PL in the high-yield strain 6#-7 is investigated, and a possible mechanism is then revealed. These findings provide a theoretical basis for further improving the production of ε-PL.

Pentacoordinated Nitrogen Atoms in the Structure of Hexalithium Bis[methylsilyl-tris(methylimide)] Hexakis(tetrahydrofuran)

1999 ◽  
Vol 54 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Gerald Huber ◽  
Alexander Jockisch ◽  
Hubert Schmidbaur
Keyword(s):  
High Yield ◽  
Cage Structure ◽  
Lithium Amide ◽  
Analogous Compound

Lithiation of tris(methylamino)methylsilane using an excess of n -butyllithium affords the corresponding trifunctional lithium amide in high yield. The compound crystallizes from tetrahydrofuran as a dimer with six donor molecules: {[MeSi(NMeLi)3]2(thf)6}. The cluster is a cage structure grouped around a crystallographic center of inversion. The silicon and lithium atoms are tetrahedrally tetracoordinated, but the nitrogen atoms are pentacoordinated and have a square pyramidal environment of one carbon, one silicon, and three lithium atoms. Parallels can be drawn to other species with polymetallated nitrogen functions. An analogous compound was prepared from tris(methylamino)vinylsilane.

scholarly journals Ru-Sn-B/Al2O3Catalysts for Selective Hydrogenation of Methyl Oleate: Influence of the Ru/Sn Ratio

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
María A. Sánchez ◽  
Vanina A. Mazzieri ◽  
María A. Vicerich ◽  
Carlos R. Vera ◽  
Carlos L. Pieck
Keyword(s):  
Catalytic Activity ◽  
Double Bond ◽  
Methyl Ester ◽  
Methyl Oleate ◽  
Carbonyl Group ◽  
Catalytic Hydrogenation ◽  
Oleyl Alcohol ◽  
High Yield ◽  
Stearyl Alcohol ◽  
Global Activity

This study focuses on the influence of the Ru/Sn ratio on the catalytic hydrogenation of methyl oleate to oleyl alcohol using Ru-Sn-B catalysts, notably on the catalytic activity and selectivity. Sn addition acts positively over the oleyl selectivity by reducing the rates of C=O and C=C saturation but also decreases the global activity. The catalyst with the highest activity and selectivity towards oleyl alcohol is Ru(1%)-Sn(2%)-B/Al2O3. At a low Sn loading (0.5%) the catalyst has high activity for hydrogenation of the carbonyl group and the carbon-carbon double bond. As a consequence stearyl alcohol is produced with high yield. At a high Sn content (4%) the catalyst has lower selectivity to oleyl alcohol due to its low capacity for hydrogenating the carbonyl group. However it has enough activity for hydrogenating the C=C double bonds to produce the saturated methyl ester.

Catalytic Hydrogenation of Phosphate Enol Esters Present in Branched Chain Dienepyranosides in a Route to Thromboxane Analogs from D-Galactose

1999 ◽  
Vol 18 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Oscar Moradei ◽  
Cecile M. du Mortier ◽  
Alicia Fernández Cirelli ◽  
Joachim Thiem
Keyword(s):  
Catalytic Hydrogenation ◽  
Enol Esters ◽  
Branched Chain

Oxidation of carbohydrates with chromium trioxide in acetic acid. I. Glycosides

1970 ◽  
Vol 23 (6) ◽  
pp. 1209 ◽  
Author(s):  
SJ Angyal ◽  
K James
Keyword(s):  
Acetic Acid ◽  
Hydrogen Atom ◽  
Catalytic Hydrogenation ◽  
Chromium Trioxide ◽  
Keto Ester ◽  
Keto Esters ◽  
Branched Chain ◽  
Acetyl Migration

Fully acetylated methyl β-D-hexopyranosides are oxidized by chromium trioxide in acetic acid to acetylated methyl 5-hexulosonates. Catalytic hydrogenation of these keto esters leads into the L-series. The corresponding a-D-glycosides are not oxidized in the same way, with the exception of methyl tetra-O-acetyl-α-D-idopyranoside. Both α- and β-anomers of the acetylated fnranosides are oxidized to aoetylated methyl 4-hexulosonates. The octaacetates of α- and β-lactose are similarly oxidized, the ring of the galactose moiety being opened. The methyl pyranoside of a branched-chain sugar, with no hydrogen atom on C5, is oxidized to a 4-keto ester, acetyl migration occurring from O4 to O5.

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