scholarly journals Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via Intramolecular 1,3-Dipolar Cycloaddition

2019 ◽  
Author(s):  
Yulia V Khoroshunova ◽  
Denis A Morozov ◽  
Andrey I Taratayko ◽  
Polina D Gladkikh ◽  
Yuri I Glazachev ◽  
...  
Keyword(s):  
Ring Opening ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Kinetics Of ◽  
Kinetics Of Reduction

Sterically shielded nitroxides of pyrrolidine series are known to demonstrate the highest stability to reduction. Here we report on the synthesis of new pyrrolidine nitroxides from 5,5-dialkyl-1-pyrroline N-oxides via the introduction of pent-4-enyl group to nitrone atom followed by intramolecular 1,3-dipolar cycloaddition reaction and isoxazolidine ring opening. Kinetics of reduction of the new nitroxides with ascorbate was studied and compared to that of previously published 1S,2R,3′S,4′S,5′S,2″R-dispiro[(2-hydroxymethyl)-cyclopentan-1,2′-(3′,4′-di-tert-butoxy)pyrrolidine-5′,1″-(2″-hydroxymethyl)cyclopentane]-1′-oxyl (1).

scholarly journals Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

2019 ◽  
Vol 15 ◽  
pp. 2036-2042
Author(s):  
Yulia V Khoroshunova ◽  
Denis A Morozov ◽  
Andrey I Taratayko ◽  
Polina D Gladkikh ◽  
Yuri I Glazachev ◽  
...  
Keyword(s):  
Ring Opening ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Kinetics Of ◽  
Kinetics Of Reduction

Sterically shielded nitroxides of the pyrrolidine series have shown the highest resistance to reduction. Here we report the synthesis of new pyrrolidine nitroxides from 5,5-dialkyl-1-pyrroline N-oxides via the introduction of a pent-4-enyl group to the nitrone carbon followed by an intramolecular 1,3-dipolar cycloaddition reaction and isoxazolidine ring opening. The kinetics of reduction of the new nitroxides with ascorbate were studied and compared to those of previously published (1S,2R,3′S,4′S,5′S,2″R)-dispiro[(2-hydroxymethyl)cyclopentan-1,2′-(3′,4′-di-tert-butoxy)pyrrolidine-5′,1″-(2″-hydroxymethyl)cyclopentane]-1′-oxyl (1).

1,3-Dipolar cycloaddition reactions of phthalic anhydrides with an azomethine ylide

2015 ◽  
Vol 2 (6) ◽  
pp. 705-712 ◽  
Author(s):  
Hugo Santos ◽  
Amy Distiller ◽  
Asha M. D'Souza ◽  
Quentin Arnoux ◽  
Jonathan M. White ◽  
...  
Keyword(s):  
Ring Opening ◽  
Cycloaddition Reaction ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Ring Opening Reaction ◽  
Phthalic Anhydrides

A series of phthalic anhydrides underwent a 1,3-dipolar cycloaddition reaction with N-benzylazomethine ylide to produce unstable spiro(isobenzofuran-1,5′-oxazolidin)-3-ones, which underwent a subsequent reductive ring-opening reaction to afford 1(3H)-isobenzofuranones.

New Pyrrolo[1,2-b]pyridazine Derivatives by 1,3-Dipolar Cycloaddition of Mesoionic Oxazolopyridazinone

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Miron Teodor Caproiu ◽  
Florea Dumitrascu ◽  
Mino R. Caira
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Pyridazine Derivatives ◽  
New Compounds

New pyrrolo[1,2-b]pyridazine derivatives 8a-f were synthesized by 1,3-dipolar cycloaddition reaction between mesoionic 1,3-oxazolo[3,2-b]pyridazinium-2-oxides and diethyl or diisopropyl acetylenedicarboxylate as alkyne dipolarophiles. The structures of the new compounds were assigned by elemental analysis and NMR spectroscopy.

Copper-catalyzed Convenient Synthesis and SAR Studies of Substituted-1,2,3-triazole as Antimicrobial Agents

2018 ◽  
Vol 16 (1) ◽  
pp. 3-10
Author(s):  
Aniket P. Sarkate ◽  
Kshipra S. Karnik ◽  
Pravin S. Wakte ◽  
Ajinkya P. Sarkate ◽  
Ashwini V. Izankar ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Agents ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
One Pot ◽  
Triazole Derivatives ◽  
Sar Studies ◽  
Convenient Synthesis ◽  
Antibacterial And Antifungal

Background:A novel copper-catalyzed synthesis of substituted-1,2,3-triazole derivatives has been developed and performed by Huisgen 1,3-dipolar cycloaddition reaction of azides with alkynes. The reaction is one-pot multicomponent.Objective:We state the advancement and execution of a methodology allowing for the synthesis of some new substituted 1,2,3-triazole analogues with antimicrobial activity.Methods:A series of triazole derivatives was synthesized by Huisgen 1,3-dipolar cycloaddition reaction of azides with alkynes. The structures of the synthesized compounds were elucidated and confirmed by 1H NMR, IR, MS and elemental analysis. All the synthesized compounds were tested for their antimicrobial activity against a series of strains of Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and against the strains of Candida albicans, Aspergillus flavus and Aspergillus nigar for antifungal activity, respectively.Results and Conclusion:From the antimicrobial data, it was observed that all the newly synthesized compounds showed good to moderate level of antibacterial and antifungal activity.

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

Kinetics of the Imidazolium Ring-Opening of mRNA 5'-cap Analogs in Aqueous Alkali

2006 ◽  
Vol 71 (4) ◽  
pp. 567-578 ◽  
Author(s):  
Alicja Stachelska ◽  
Zbigniew J. Wieczorek ◽  
Janusz Stępiński ◽  
Marzena Jankowska-Anyszka ◽  
Harri Lönnberg ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Ring Opening ◽  
Nucleophilic Attack ◽  
Amino Groups ◽  
Hydroxide Ion ◽  
Methyl Group ◽  
Structural Modifications ◽  
Alkyl Groups ◽  
Imidazolium Ring ◽  
Kinetics Of

Second-order rate constants for the hydroxide-ion-catalyzed imidazolium ring-opening of several mono- and dinucleosidic analogs of mRNA 5'-cap have been determined. Intramolecular stacking of the two nucleobases in the dinucleosidic analogs, m7GpppN (m7G = 7-methylguanosine, N = 5'-linked nucleoside), and electrostatic interaction between the N-alkylated imidazolium ring and phosphate moiety have been shown to shield the m7G moiety against the nucleophilic attack of hydroxide ion. In addition, the effect of methylation of the nucleobase amino groups and replacement of the 7-methyl group with other alkyl groups have been studied. The influence of all the structural modifications studied turned out to be modest, the cleavage rates of the most and least reactive analogs (with the exception of non-phosphorylated nucleosides) differing only by a factor of 5.

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