scholarly journals Convenient synthesis of the pentasaccharide repeating unit corresponding to the cell wall O-antigen of Escherichia albertii O4

2020 ◽  
Vol 16 ◽  
pp. 106-110 ◽  
Author(s):  
Tapasi Manna ◽  
Arin Gucchait ◽  
Anup Kumar Misra
Keyword(s):  
Cell Wall ◽  
Perchloric Acid ◽  
Good Yield ◽  
Protecting Groups ◽  
O Antigen ◽  
Synthetic Strategy ◽  
Convenient Synthesis ◽  
Selection Of ◽  
Glycosyl Donors

A straightforward sequential synthetic strategy has been developed for the synthesis of a pentasaccharide repeating unit corresponding to the cell wall O-antigen of the Escherichia albertii O4 strain in very good yield with the desired configuration at the glycosidic linkages using thioglycosides and trichloroacetimidate derivatives as glycosyl donors and perchloric acid supported over silica (HClO4/SiO2) as a solid supported protic acid glycosyl activator. The expected configuration at the glycosidic linkages was achieved using a reasonable selection of protecting groups in the manosaccharide intermediates.

scholarly journals Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71T using linear and one-pot iterative glycosylations

2020 ◽  
Vol 16 ◽  
pp. 1700-1705
Author(s):  
Arin Gucchait ◽  
Pradip Shit ◽  
Anup Kumar Misra
Keyword(s):  
Perchloric Acid ◽  
Good Yield ◽  
Type Strain ◽  
One Pot ◽  
Synthetic Strategy ◽  
Specific Polysaccharide ◽  
Glycosyl Donors

A straightforward synthetic strategy was developed for the synthesis of the tetrasaccharide repeating unit corresponding to the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71T in a very good yield adopting sequential glycosylation followed by removal of the p-methoxybenzyl (PMB) group in the same pot. Further, the synthetic strategy was modified by carrying out three stereoselective iterative glycosylations followed by in situ removal of the PMB group in one pot. The stereochemical outcome of the newly formed glycosidic linkages was excellent using thioglycoside derivatives as glycosyl donors and a combination of N-iodosuccinimide (NIS) and perchloric acid supported on silica (HClO4-SiO2) as the glycosyl activator.

scholarly journals Synthesis of Pentasaccharide Repeating Unit Corresponding to the Cell Wall O-Polysaccharide of Salmonella enterica O55 Strain Containing a Rare Sugar 3-Acetamido-3-deoxy-d-fucose

Synthesis ◽  
2021 ◽  
Author(s):  
Anup Kumar Misra ◽  
Arin Gucchait ◽  
Monalisa Kundu
Keyword(s):  
Cell Wall ◽  
Salmonella Enterica ◽  
Good Yield ◽  
Rare Sugar ◽  
Stereoselective Glycosylation ◽  
O Antigen ◽  
Excellent Yield ◽  
Glycosylation Reaction

AbstractA pentasaccharide repeating unit corresponding to the cell wall O-antigen of Salmonella enterica O55 containing a rare sugar, 3-acetamido-3-deoxy-d-fucose has been synthesized as its p-methoxyphenyl glycoside using a sequential stereoselective glycosylation strategy. A suitably functionalized 3-azido-3-deoxy-d-fucose thioglycoside derivative was prepared in very good yield and used in the stereoselective glycosylation reaction. Functionalized monosaccharide intermediates were prepared judiciously and stereoselectively assembled to get the desired pentasaccharide derivative in excellent yield.

scholarly journals Synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4

2014 ◽  
Vol 10 ◽  
pp. 2724-2728 ◽  
Author(s):  
Pintu Kumar Mandal
Keyword(s):  
E Coli ◽  
O Antigen ◽  
Synthetic Strategy ◽  
Glycosyl Donors

The pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4 strain has been synthesized using a combination of sequential glycosylations and [3 + 2] block synthetic strategy from the suitably protected monosaccharide intermediates. Thioglycosides and glycosyl trichloroacetimidate derivatives have been used as glycosyl donors in the glycosylations.

On the Chemistry of Ingenol, III [1] Synthesis of 3-Deoxy-3-oxoingenol, Some 5-Esters and of Ethers and Acetals of Ingenol

1982 ◽  
Vol 37 (12) ◽  
pp. 1640-1647 ◽  
Author(s):  
Bernd Sorg ◽  
Erich Hecker
Keyword(s):  
Good Yield ◽  
Protecting Groups ◽  
Silyl Ether ◽  
Subsequent Removal ◽  
Mouse Ear

3-Deoxy-3-oxoingenol (3) was prepared from ingenol-5,20-acetonide (25) by oxidation and subsequent removal of the acetonide. 3 was acylated to give homologous 5,20-diacylates 5-9. From these the 5-monoacylates 14, 15 and 17 were obtained in only moderate yields. Therefore the 20-silyl ether 10 (prepared from 3) was acylated. After smooth removal of the silyl ether the homologous 5-acylates 16. 18 and 19 resulted in good yield. The 5,20-dibutyrate 6 and all 5-acylates prepared (14-19) showed no irritant activity on the mouse ear. The 3-oxo-5-acylates 14-19 could not be reduced to give ingenol-5-acylates (24). Therefore various ingenol derivatives, 29-32, with suitable protected hydroxyl functions as well as the corresponding 5-clecanoates 35-38 were synthesized. The protecting groups of the derivatives 35-38 could however not be cleaved off to yield ingenol-5- decanoate (24)

scholarly journals The efficient synthesis of 1-deoxymannojirimycin and its derivatives

2021 ◽  
Author(s):  
◽  
Benjamin Mark Mandinka Deeble
Keyword(s):  
Total Synthesis ◽  
Lysosomal Storage Diseases ◽  
Heterocyclic Ring ◽  
Lysosomal Storage ◽  
Synthetic Strategy ◽  
Anti Cancer ◽  
Structural Analogues ◽  
Treatment Of Diabetes ◽  
Significant Effort ◽  
Selection Of

<p>Azasugars are structural analogues of carbohydrates whereby the oxygen in the heterocyclic ring is substituted for a nitrogen. These carbohydrates are an important class of compounds with medicinal bioactivities and have shown potential for the treatment of diabetes, viral-infection, cancers, and lysosomal storage diseases. 1-deoxymannojirimycin (DMJ), is a mannosidase inhibiting azasugar which has shown anti-cancer and anti-viral activity. There has been significant effort put towards developing methodology to produce this compound and libraries of its derivatives. This thesis presents the synthesis of DMJ and a selection of its derivatives via an efficient 4 step methodology from a carbohydrate starting material, exploiting chemo and regioselective reactions to allow for a total synthesis with minimal use of protecting groups. The synthesis of DMJ, using the methodology developed herein, surpasses published syntheses in efficiency. This synthetic strategy was then used for the preparation of N-functionalised DMJ derivatives without the requirement of additional synthetic steps. To illustrate the versatility of this methodology, a selection of derivatives incorporating different functionalities have been synthesised.</p>

scholarly journals Influence of the method of disintegration of biomass of microalga Chlorella sorokiniana on the production of lipid fraction

2019 ◽  
Vol 59 (7) ◽  
pp. 85-91
Author(s):  
Yulia A. Smyatskaya ◽  
◽  
Natalia A. Politaeva ◽  
Amira Toumi ◽  
◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cell Wall ◽  
Microwave Radiation ◽  
High Speed ◽  
Unsaturated Fatty Acids ◽  
Lipid Fraction ◽  
Chlorella Sorokiniana ◽  
Lipid Fractions ◽  
Significant Difference ◽  
Selection Of

This article discusses the effect of the disintegration of the cell wall of the microalgae Chlorella sorokiniana on the output of the lipid fraction. The biomass of the microalgae Chlorella sorokiniana was grown under laboratory conditions in special photobioreactors at a temperature of 25 °C, with a constant aeration of a mixture of carbon dioxide and air at a rate of 1.5 liters/min, illumination 2200-2800 Lx. Nutrient medium for cultivation contained macro – and micronutrients for high-speed growth of microalgae. Selection of optimal cultivation parameters allows obtaining biomass with desired properties. Disintegration was carried out with the homogenization of biomass and under the influence of microwave radiation. Extraction of lipids was carried out on a semi-automatic extractor according to the Randall method, using organic solvents. The output of the lipid fraction without treatment was 10.18% after the destruction of the cell wall 14.45% with the homogenization of biomass and 13.85% under the influence of microwave radiation. A qualitative analysis of the lipid fraction, carried out under gas chromatography, obtained under various conditions showed that there was no significant difference in composition from the disintegration method. Lipid fractions (more than 50%) in both cases consist mainly of unsaturated fatty acids, of which irreplaceable unsaturated fatty acids constitute more than 18% for both samples. The residual biomass formed after the extraction of the lipid fraction can be used as fertilizer in the plant, for the manufacture of sorption materials for the purification of industrial water and as a biofuel. The purpose of this study was to study the effect of cell wall disintegration on the output of the lipid fraction and qualitative composition.

scholarly journals Synthesis of the spiroketal core of integramycin

2013 ◽  
Vol 9 ◽  
pp. 2446-2450
Author(s):  
Evgeny V Prusov
Keyword(s):  
Integrase Inhibitor ◽  
Protecting Groups ◽  
Hiv Integrase ◽  
Acylation Reaction ◽  
Synthetic Strategy

A concise synthetic strategy towards the spiroketal core of the HIV-integrase inhibitor integramycin (1) was developed. The required ketone precursor was efficiently constructed from two simple and easily accessible subunits by means of a hydrozirconation/copper catalyzed acylation reaction. The effects of different protecting groups on the spiroketalization step were also investigated.

A Simple Synthesis of 4-Substituted 2-(3-Hydroxy-2-oxo-1-phenethylpropylcarbamoyl) pyrrolidine-1-carboxylic Acid Benzyl Esters as Novel Cysteine Protease Inhibitors

2008 ◽  
Vol 63 (2) ◽  
pp. 210-216 ◽  
Author(s):  
Seikwan Oh ◽  
Jae-Chul Jung ◽  
Mitchell A. Avery
Keyword(s):  
Carboxylic Acid ◽  
Protease Inhibitors ◽  
Cysteine Protease ◽  
Good Yield ◽  
Sodium Acetate ◽  
Simple Synthesis ◽  
Insertion Reaction ◽  
Cysteine Protease Inhibitors ◽  
Convenient Synthesis ◽  
Benzyl Esters

A convenient synthesis of 4-substituted 2-(3-hydroxy-2-oxo-1-phenethylpropylcarbamoyl)pyrrolidine- 1-carboxylic acid benzyl esters 17 and 18 as new cysteine protease inhibitors is described. The synthetic key strategies involve the diazocarbonyl insertion reaction of N-Boc-L-homophenylalanine (1) by diazomethane, acetylation of the bromoketone 2 with sodium acetate, and condensation of acids 12, 14 with (3S)-3-amino-2-oxo-5-phenyl-pentyl acetate monohydrochloride (4) in good yield

The AA* + B*B2 approach A simple and convenient synthetic strategy towards hyperbranched polyurea-urethanes

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Bernd Bruchmann ◽  
Wolfgang Schrepp
Keyword(s):  
Functional Groups ◽  
Raw Materials ◽  
Protecting Groups ◽  
Isophorone Diisocyanate ◽  
Step Process ◽  
Synthetic Strategy ◽  
One Step

Abstract Synthesizing hyperbranched polyurethanes in a one step process using commercially available raw materials: these were the primary conditions for this work. By taking advantage of intramolecular reactivity differences of isocyanate groups in diisocyanates in combination with reactivity differences of OH and NH groups in alkanolamines, it is possible to generate in situ AB2 molecules by controlling reactions of specific functional groups towards each other. This AA* + B*B2 approach works without protecting groups and opens up a simple and versatile strategy towards hyperbranched aromatic as well as aliphatic polyureaurethanes. Preferential diisocyanates for this synthesis were 2,4-toluylene diisocyanate and isophorone diisocyanate, whereas diethanolamine and diisopropanolamine were used as isocyanate-reactive counterparts.

Sign in / Sign up

Export Citation Format

Share Document