Preparation and spectral properties of products of the reaction of N,N-dimethylhydrazine with selected enolethers/alkoxymethylene systems

Tarabová, Denisa; Milata, Viktor

doi:10.2478/v10188-012-0035-x

Cited by 2 publications

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References 3 publications

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“…8a , 9a , 9b , 10a were also described, but their characterization is insufficient in the cited literature. Therefore, we prepared and characterized all the compounds and published their syntheses separately …”

Section: Methodsmentioning

confidence: 99%

Kinetics and mechanism of the reaction of alkoxymethylidene malonate and malononitrile with hydrazines and anilines

Tarabová

Milata

Hanusek

2013

J of Physical Organic Chem

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The kinetics and mechanism of the nucleophilic vinylic substitution of dialkyl (alkoxymethylidene)malonates (alkyl: methyl, ethyl) and (ethoxymethylidene)malononitrile with substituted hydrazines and anilines R 1 -NH 2 (R 1 : (CH 3 ) 2 N, CH 3 NH, NH 2 , C 6 H 5 NH, CH 3 CONH, 4-CH 3 C 6 H 4 SO 2 NH, 3-and 4-X-C 6 H 4 ; X: H, 4-Br, 4-CH 3 , 4-CH 3 O, 3-Cl) were studied at 25 C in methanol. It was found that the reactions with all hydrazines (the only exception was the reaction of (ethoxymethylidene)malononitrile with N,N-dimethylhydrazine) showed overall second-order kinetics and k obs were linearly dependent on the hydrazine concentration which is consistent with the rate-limiting attack of the hydrazine on the double bond of the substrate. Corresponding Brønsted plots are linear (without deviating N-methyl and N, N-dimethylhydrazine), and their slopes (b Nuc ) gradually increase from 0.59 to 0.71 which reflects gradually increasing order of the C-N bond formed in the transition state. The deviation of both methylated hydrazines is probably caused by the different site of nucleophilicity/basicity in these compounds (tertiary/secondary vs. primary nitrogen). A somewhat different situation was observed with the anilines (and once with N,N-dimethylhydrazine) where parabolic dependences of the kinetics gradually changing to linear dependences as the concentration of nucleophile/base increases. The second-order term in the nucleophile indicates the presence of a steady-state intermediate -most probably T AE . Brønsted and Hammett plots gave b Nuc = 1.08 and r = À3.7 which is consistent with a late transition state whose structure resembles T AE .

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Section: Methodsmentioning

confidence: 99%

Kinetics and mechanism of the reaction of alkoxymethylidene malonate and malononitrile with hydrazines and anilines

Tarabová

Milata

Hanusek

2013

J of Physical Organic Chem

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Two novel potent perfluorophenylhydrazone derivatives, 1-((4-bromothiophen-2-yl)methylene)-2-(perfluorophenyl) hydrazine, and 1-((4-bromo-5-methylthiophen-2-yl)methylene)-2-(perfluorophenyl)hydrazine as multi-target compounds to combat Alzheimer disease and their crystal, molecular, and electronic properties

Sivý,

Bortňák,

Végh

et al. 2023

Acta Chimica Slovaca

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Two potent novel perfluorophenylhydrazone derivatives are presented as multi-target compounds to combat Alzheimer disease C11H4BrF5N2S, 1-((4-bromothiophen-2-yl)methylene)-2-(perfluorophenyl) hydrazine, (I) and C12H6BrF5N2S, 1-((4-bromo-5-methylthiophen-2-yl)methylene)-2-(perfluorophenyl) hydrazine, (II), which can potentially be improved by further design. Their multi-target structures and features have been combined as potential AD therapeutics. Crystals (I), and (II), are molecules with two rings and a hydrazone part as a centre of the molecule. The compounds have been synthesised and characterised by elemental spectroscopic (1H-NMR) analysis. Crystal structures of the solid phase were determined by single crystal X-ray diffraction method. Both compounds crystallise in the monoclinic space group with Z = 4 and Z = 2 molecules per unit-cell. Compound (I) crystallises as a racemate in the centrosymmetric space group and compound (II) crystallises as a non-racemate in the non-centrosymmetric space group. Their “absolute configuration and conformation for bond values” were derived from the anomalous dispersion (rmad) for (II). Crystal structures revealed diverse non-covalent interactions such as intra- and inter-hydrogen bonding, π-ring…π-ring, C—H…π-ring. The expected stereochemistry of hydrazones atoms C7, N2 and N1 were confirmed for (I) and (II). Both molecules show “boat conformation” like a 6-membered ring. Results of single crystal studies were reproduced with the help of Hirshfeld surface study and Gaussian software.

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Preparation and spectral properties of products of the reaction of N,N-dimethylhydrazine with selected enolethers/alkoxymethylene systems

Cited by 2 publications

References 3 publications

Kinetics and mechanism of the reaction of alkoxymethylidene malonate and malononitrile with hydrazines and anilines

Kinetics and mechanism of the reaction of alkoxymethylidene malonate and malononitrile with hydrazines and anilines

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