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 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 One-pot synthesis of (R)-convolutamydine A involving in situ chiral organocatalyst formation

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Shengwei Wei ◽  
Bernhard Schmid ◽  
Fliur Z. Macaev ◽  
Serghei N. Curlat ◽  
Andrei V. Malkov ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
One Pot ◽  
One Pot Synthesis ◽  
Synthetic Strategy

Abstract The application of a convenient one-pot synthetic strategy, utilizing an in situ formed organocatalyst, to the enantioselective synthesis of anti-leukaemia agent (R)-convolutamydine A has been demonstrated.

scholarly journals A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis- N -heterocycles: rationalization by electronic structure calculations

2018 ◽  
Vol 5 (9) ◽  
pp. 181140 ◽  
Author(s):  
Liliana Damas ◽  
Rui M. B. Carrilho ◽  
Sandra C. C. Nunes ◽  
Alberto A. C. C. Pais ◽  
László Kollár ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Reaction Conditions ◽  
One Pot ◽  
New Family ◽  
Synthetic Strategy ◽  
Heterocyclic Derivatives ◽  
Amine Groups ◽  
Structure Calculations

An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N -nucleophiles, gives access, in one pot, to a new family of indole-based N -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( P CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1 S , 2S )-(+)-cyclohexane-1,2-diamine ( a ) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

Cyclic Alkyne Approach to Heteroatom-Containing Polycyclic Aromatic Hydrocarbon Scaffolds

2019 ◽  
Author(s):  
Evan Darzi ◽  
Joyann Barber ◽  
Neil Garg
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Diels Alder ◽  
Pericyclic Reactions ◽  
One Pot ◽  
Synthetic Strategy ◽  
Polycyclic Aromatic

We report a modular synthetic strategy for accessing heteroatom-containing polycyclic aromatic hydrocarbons (PAHs) that relies on the controlled generation of transient heterocyclic alkynes and arynes. The strained intermediates undergo in situ trapping with readily accessible oxadiazinones. Four sequential pericyclic reactions occur, namely two Diels–Alder / retro-Diels–Alder sequences, which can be performed in a stepwise or one-pot fashion to assemble four new carbon–carbon (C–C) bonds.

scholarly journals Benzyne arylation of oxathiane glycosyl donors

2010 ◽  
Vol 6 ◽  
Author(s):  
Martin A Fascione ◽  
W Bruce Turnbull
Keyword(s):  
Lead Tetraacetate ◽  
One Pot ◽  
Glycosyl Donors

The arylation of bicyclic oxathiane glycosyl donors has been achieved using benzyne generated in situ from 1-aminobenzotriazole (1-ABT) and lead tetraacetate. Following sulfur arylation, glycosylation of acetate ions proceeded with high levels of stereoselectivity to afford α-glycosyl acetates in a ‘one-pot’ reaction, even in the presence of alternative acceptor alcohols.

Cyclic Alkyne Approach to Heteroatom-Containing Polycyclic Aromatic Hydrocarbon Scaffolds

2019 ◽  
Author(s):  
Evan Darzi ◽  
Joyann Barber ◽  
Neil Garg
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Diels Alder ◽  
Pericyclic Reactions ◽  
One Pot ◽  
Synthetic Strategy ◽  
Polycyclic Aromatic

We report a modular synthetic strategy for accessing heteroatom-containing polycyclic aromatic hydrocarbons (PAHs) that relies on the controlled generation of transient heterocyclic alkynes and arynes. The strained intermediates undergo in situ trapping with readily accessible oxadiazinones. Four sequential pericyclic reactions occur, namely two Diels–Alder / retro-Diels–Alder sequences, which can be performed in a stepwise or one-pot fashion to assemble four new carbon–carbon (C–C) bonds.

Facile one-pot synthesis of cyclic peptide-conjugated photosensitisers for targeted photodynamic therapy

2020 ◽  
Vol 56 (80) ◽  
pp. 11941-11944
Author(s):  
Jacky C. H. Chu ◽  
Caixia Yang ◽  
Wing-Ping Fong ◽  
Clarence T. T. Wong ◽  
Dennis K. P. Ng
Keyword(s):  
Photodynamic Therapy ◽  
Cyclic Peptide ◽  
One Pot ◽  
One Pot Synthesis ◽  
Synthetic Strategy ◽  
Targeted Photodynamic Therapy

A facile synthetic strategy for in situ cyclisation of peptides and conjugation with functional boron dipyrromethenes (BODIPYs) using a bifunctional linker is reported.

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

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