Curve crossing analysis of LFER data in Michael addition reactions

1992 ◽  
Vol 70 (4) ◽  
pp. 1022-1027 ◽  
Author(s):  
Zeev Gross ◽  
Shmaryahu Hoz
Keyword(s):  
Chemical Shift ◽  
Transition State ◽  
Michael Addition ◽  
Electronic Configuration ◽  
Nucleophilic Attack ◽  
Addition Reactions ◽  
Rate Correlation ◽  
The Michael Addition ◽  
Curve Crossing

Rate constants for the Michael addition of CN− in water, aqueous sulfolane, and DMSO, and MeO− in MeOH to eight mono- and disubstituted 1,1-diaryl-2,2-dinitroethylenes were measured. The ρ values are in the range 0.7 (CN−/H2O) –1.6 (MeO−/MeOH). For each of the four systems a correlation was found between log k and the 13C chemical shift of the carbon that undergoes the nucleophilic attack. However, the quality of the correlation as well as the slope decreases with decreasing ρ values. Analysis of the electronic configuration of the transition state using the curve crossing model shows that the traditional interpretation of the location of the transition state should be reversed. This analysis provides a rationale for the observed dependence of the chemical shift – rate correlation on the ρ value.

Theoretical studies on the activation mechanism involving bifunctional tertiary amine–thioureas and isatylidene malononitriles

RSC Advances ◽  
2015 ◽  
Vol 5 (43) ◽  
pp. 34314-34318 ◽  
Author(s):  
Zheng-Hang Qi ◽  
Ye Zhang ◽  
Gui-Yu Ruan ◽  
Yi Zhang ◽  
Yong Wang ◽  
...  
Keyword(s):  
Tertiary Amine ◽  
Michael Addition ◽  
Activation Mechanism ◽  
Addition Reactions ◽  
Theoretical Studies ◽  
Dft Studies ◽  
The Michael Addition

DFT studies on the activation mechanism of the Michael addition reactions containing bifunctional tertiary amine–thioureas and isatylidene malononitriles have been performed at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory.

CARCINOGENICITY OF LACTONES: I. THE REACTION OF 4-METHYLBUTENO- AND 4-METHYLBUTANO-γ-LACTONES WITH PRIMARY AMINES

1966 ◽  
Vol 44 (9) ◽  
pp. 1059-1068 ◽  
Author(s):  
J. Bryan Jones ◽  
John M. Young
Keyword(s):  
Magnetic Resonance ◽  
Michael Addition ◽  
Ring Opening ◽  
Proton Magnetic Resonance ◽  
Mechanisms Of Action ◽  
Reaction Pathways ◽  
Nucleophilic Attack ◽  
Primary Amines ◽  
Acid Lactone ◽  
The Michael Addition

As the first stage in the investigations of the mechanisms of action of carcinogenic lactones, the reactions of 4-hydroxypent-2-enoic acid lactone (II, R = CH3), which is a carcinogen, and of the non-carcinogenic 4-hydroxypent-3-enoic (III, R = CH3) and 4-hydroxypentanoic (IV, R = CH3) acid lactones with methylamine and benzylamine have been studied. As expected, the carcinogenic lactone reacts to give the Michael addition products, whereas both inactive lactones undergo ring opening by nucleophilic attack at the carbonyl group. From the relative rates of reaction of the amines with the lactones it is concluded that the induction of tumors by II (R = CH3) does not involve alkylation of biological primary alkylamino groups. The proton magnetic resonance spectra of the products enable the different reaction pathways to be distinguished readily, and may provide the basis for rapid physicochemical screening of alkylation agents that are potential carcinogens.

Carcinogenicity of lactones. IV. Alkylation of analogues of DNA guanine groups such as imidazole, N-methylimidazole, and guanosine by α, β-unsaturated acids

1970 ◽  
Vol 48 (10) ◽  
pp. 1566-1573 ◽  
Author(s):  
J. Bryan Jones ◽  
John M. Young
Keyword(s):  
Michael Addition ◽  
Alkylating Agents ◽  
Addition Reactions ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
The Michael Addition

Studies on the reactions of carcinogenic γ-lactones and related compounds with analogues of guanine DNA residues indicate that the lactones themselves will not effect permanent alkylation of the guanine N-7 position since the Michael addition reactions involved would be readily reversible. In contrast, the α,β-unsaturated acids resulting from hydrolysis of such lactones are effective guanine N-7 alkylating agents owing to zwitterionic stabilization of the corresponding Michael addition products.

A molecular electron density theory (MEDT) study of the role of halogens (X2 = F2, Cl2, Br2 and I2) on the aza-Michael-addition reactions

2020 ◽  
Vol 44 (44) ◽  
pp. 19002-19012
Author(s):  
Luis R. Domingo ◽  
Ahmad Seif ◽  
Elham Mazarei ◽  
Ehasn Zahedi ◽  
Temer S. Ahmadi
Keyword(s):  
Gas Phase ◽  
Electron Density ◽  
Michael Addition ◽  
Nucleophilic Attack ◽  
Addition Reactions ◽  
Energy Profile ◽  
Molecular Electron ◽  
Molecular Electron Density Theory

The energy profile for gas phase F2-catalyzed nucleophilic attack of PYR R1 on the β-conjugated carbon of MA R2 marked.

Preparation of a chiral Pt12 tetrahedral cage and its use in catalytic Michael addition reaction

2018 ◽  
Vol 54 (38) ◽  
pp. 4814-4817 ◽  
Author(s):  
Imtiyaz Ahmad Bhat ◽  
Anthonisamy Devaraj ◽  
Prodip Howlader ◽  
Ki-Whan Chi ◽  
Partha Sarathi Mukherjee
Keyword(s):  
Michael Addition ◽  
Self Assembly ◽  
Addition Reaction ◽  
Addition Reactions ◽  
Stoichiometric Ratio ◽  
Michael Addition Reaction ◽  
Methanol Mixture ◽  
Hexadentate Ligand ◽  
The Michael Addition

A chiral M12L4 molecular tetrahedron (T) was synthesized by self-assembly of chiral cis-[(1S,2S)-dch]Pt(NO3)2 (M) with a hexadentate ligand (L) in 3 : 1 stoichiometric ratio. The cage T was found to catalyze the Michael addition reactions of series of nitrostyrene derivatives with indole in (9 : 1) water–methanol mixture.

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