Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

Cleavage Reactions of 5-Arylazo Derivatives of 1-Methyl-2-benzyl-2-imidazolin-4-ones

1975 ◽  
Vol 30 (7-8) ◽  
pp. 603-605 ◽  
Author(s):  
Nazmi Abdel Latif Kassab ◽  
Abdel Hamid Harhash ◽  
Sanna Osman Abd Allah
Keyword(s):  
Sodium Hydroxide Solution ◽  
Aqueous Sodium Hydroxide ◽  
The Other ◽  
Ring Cleavage ◽  
Prolonged Heating ◽  
Aqueous Sodium Hydroxide Solution ◽  
Aqueous Sodium ◽  
Triazine Derivatives ◽  
Cleavage Reactions ◽  
Derivatives Of

The 5-arylazo-1-methyl-2-benzyl-2-imidazolin-4-ones (1 a-c) undergo ring cleavage with 1% aqueous sodium hydroxide solution affording α-arylhydrazono-phenacetyl-sarcosine amide (2). Prolonged heating of 1 and 2 with the same reagent yields the cyanamide (3). On the other hand, when 1 a-c were refluxed with acetic acid the triazinones (4) were obtained. The latter adds one mole of Grignards reagent to yield the 5-hydroxy-1,2,4-triazine derivatives (5).

scholarly journals Catalytic Asymmetric Fluorination of Alkyl 1-indanone-2-carboxylates Ruled by Pybox-Eu(III) Combination

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1141 ◽  
Author(s):  
Albert Granados ◽  
Pau Sarró ◽  
Adelina Vallribera
Keyword(s):  
Catalytic Method ◽  
Reaction Conditions ◽  
Catalytic Asymmetric ◽  
Derivatives Of ◽  
Fluoro Derivatives

A highly enantioselective catalytic method for the synthesis of quaternary α-fluoro derivatives of 3-oxo esters is described. The reaction uses europium (III) triflate and commercially available chiral pybox-type C2-symmetric ligand. Excellent results in terms of yields and enantioselectivities were assured using the electrophilic NFSI reagent under mild reaction conditions.

Époxydes α-éthyléniques et phénate de sodium: accès à des éthers phénoliques et phénols ortho-allyliques

1985 ◽  
Vol 63 (9) ◽  
pp. 2449-2454 ◽  
Author(s):  
Michèle David ◽  
Jean Sauleau ◽  
Armelle Sauleau
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Steric Hindrance ◽  
Transition States ◽  
Ring Cleavage ◽  
Reaction Conditions ◽  
Carbon Compounds ◽  
Judicious Choice ◽  
Ethylenic Carbon ◽  
Cleavage Reactions

The ring cleavage reactions of α-ethylenic epoxides by sodium phenoxide afforded a mixture of products. Problems of competitive attack by this nucleophile, at the less substituted carbon (compounds A) or at the β-ethylenic carbon atom (compounds B and C), were encountered and could be resolved by judicious choice of reaction conditions (solvents, stereochemistry of the oxiranes). The regioselectivity of the attack was dependent on the transition states, implying weak steric hindrance and a conjugation oxirane – double bond.

Aziridine Ring Cleavage by Nucleophiles in Epimino Derivatives of 1,6-Anhydro-β-D-hexopyranoses

2002 ◽  
Vol 2002 (15) ◽  
pp. 2449 ◽  
Author(s):  
Jiří Kroutil ◽  
Tomáš Trnka ◽  
Miloš Buděšínský ◽  
Miloslav Černý
Keyword(s):  
Ring Cleavage ◽  
Aziridine Ring ◽  
Derivatives Of

Synthesis and Characterization of Pendant Arm Encapsulated Complexes of Cobalt(III)

1989 ◽  
Vol 42 (5) ◽  
pp. 649 ◽  
Author(s):  
AA Achilleos ◽  
LR Gahan ◽  
KA Nicolaidis
Keyword(s):  
Convenient Method ◽  
Acidic Solution ◽  
Synthesis And Characterization ◽  
Protecting Group ◽  
Chromatographic Purification ◽  
Chemical Modifications ◽  
Reaction Conditions ◽  
Pendant Arm ◽  
Derivatives Of

The synthesis and characterization of an octahedral cobalt(III) complex of the octaamine ligand 5,5-bis(4-amino-2-azabutyl)-3,7-diazanonane-1,9-diamine, [co( asen )]3+, is described. Two approaches to the preparation of encapsulated derivatives of [Co(asen)]3+ are also described. The first approach involves reaction of [Co(asen)]3+ with nitromethane and formaldehyde in the presence of base. After extensive chromatographic purification [(1-(4-amine-2-azabutyl)-8-nitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane )cobalt(III)]5+ was isolated. The second more convenient method employs precautionary protection of the pendant primary amine of [Co( asen )]3+, as the benzenesulfonate, prior to reaction with the same capping reagents. Both approaches result in an encapsulated complex bearing a pendant 4-amine-2-azabutyl moiety. The protecting group is stable under reaction conditions required for successive chemical modifications of the capping nitro group to amine, chloro and proton capped cages, but is readily removed in refluxing acidic solution.

Preparation of selectively protected derivatives of 21-nor-5-pregnene-3β,20-diol

1990 ◽  
Vol 55 (2) ◽  
pp. 499-511 ◽  
Author(s):  
Vladimír Pouzar ◽  
Dalibor Sameš ◽  
Miroslav Havel
Keyword(s):  
Vinyl Ether ◽  
Ethyl Vinyl Ether ◽  
Protecting Group ◽  
Subsequent Removal ◽  
Reaction Conditions ◽  
Ethyl Vinyl ◽  
Hydride Reduction ◽  
Acid Catalyzed ◽  
Methyl Vinyl Ether ◽  
Derivatives Of

The preparation of selectively protected derivatives of the title diol (III) is described. Derivatives with protected hydroxyl in position 3 (IV, V and VI) were obtained by p-toluenesulfonic acid-catalyzed reaction of etienic acid (I) with dihydropyran, ethyl vinyl ether and methyl vinyl ether, respectively, and subsequent hydride reduction. The protection of the free primary hydroxyl in these compounds and the subsequent removal of the acetal protecting group in position 3 represents a suitable approach to 20-protected derivatives. The relative rates of cleavage of the acetal protecting groups and reaction conditions are discussed.

Metabolism of Benzoic Acids and Phenols in Cell Suspension Cultures of Soybean and Mung Bean

1978 ◽  
Vol 33 (5-6) ◽  
pp. 363-367 ◽  
Author(s):  
Wolfgang Barz ◽  
Rita Schlepphorst ◽  
Peter Wilhelm ◽  
Karl Kratzl ◽  
Erich Tengler
Keyword(s):  
Cell Suspension ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Ring Cleavage ◽  
Benzoic Acids ◽  
Veratric Acid ◽  
Nitrobenzoic Acids ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Soybean Cell

Abstract Uptake of benzoic and salicylic acid by soybean cell suspension cultures is diffusion-mediated and exclusively leads to glucose-esters. - Veratric acid is para-demethylated to vanillic acid which is conjugated to a monoglucoside. - Nitrobenzoic acids are scarcely taken up by cell cultures with glucose-esters as sole products. - Ring-labelled derivatives of vanillylalcohol and creosol are mainly polymerized to insoluble structures, ring cleavage reactions could not be observed.

The Chemistry of Derivatives of 2-Benzaltetralone. IV.1The Synthesis, Spectra and Ring Cleavage Reactions of Some Spiroepoxyketones

1959 ◽  
Vol 81 (16) ◽  
pp. 4294-4298 ◽  
Author(s):  
Norman H. Cromwell ◽  
Ronald E. Bambury ◽  
Raymond P. Barkley
Keyword(s):  
Ring Cleavage ◽  
Cleavage Reactions ◽  
Derivatives Of

ChemInform Abstract: Fluorinated Carbohydrates as Potential Plasma Membrane Modifiers. Synthesis of 4- and 6-Fluoro Derivatives of 2-Acetamido-2-deoxy-D-hexopyranoses.

ChemInform ◽  
1990 ◽  
Vol 21 (41) ◽  
Author(s):  
M. SHARMA ◽  
R. J. BERNACKI ◽  
B. PAUL ◽  
W. KORYTNYK
Keyword(s):  
Plasma Membrane ◽  
Derivatives Of ◽  
Fluoro Derivatives

scholarly journals Self-Supporting Hydrogels Based on Fmoc-Derivatized Cationic Hexapeptides for Potential Biomedical Applications

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Carlo Diaferia ◽  
Elisabetta Rosa ◽  
Enrico Gallo ◽  
Giovanni Smaldone ◽  
Mariano Stornaiuolo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Supporting Cell ◽  
Diagnostic Tools ◽  
Cationic Peptides ◽  
Protecting Group ◽  
Synthetic Hydrogel ◽  
Acetyl Group ◽  
Biophysical Techniques ◽  
Fmoc Protecting Group ◽  
Derivatives Of

Peptide-based hydrogels (PHGs) are biocompatible materials suitable for biological, biomedical, and biotechnological applications, such as drug delivery and diagnostic tools for imaging. Recently, a novel class of synthetic hydrogel-forming amphiphilic cationic peptides (referred to as series K), containing an aliphatic region and a Lys residue, was proposed as a scaffold for bioprinting applications. Here, we report the synthesis of six analogues of the series K, in which the acetyl group at the N-terminus is replaced by aromatic portions, such as the Fmoc protecting group or the Fmoc-FF hydrogelator. The tendency of all peptides to self-assemble and to gel in aqueous solution was investigated using a set of biophysical techniques. The structural characterization pointed out that only the Fmoc-derivatives of series K keep their capability to gel. Among them, Fmoc-K3 hydrogel, which is the more rigid one (G’ = 2526 Pa), acts as potential material for tissue engineering, fully supporting cell adhesion, survival, and duplication. These results describe a gelification process, allowed only by the correct balancing among aggregation forces within the peptide sequences (e.g., van der Waals, hydrogen bonding, and π–π stacking).

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