𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Transmission of substituent effects in heterocyclic systems. Variation of the Hammett ρ with the aromatic substrate.

✍ Scribed by David A. Forsyth; Donald S. Noyce

Publisher
Elsevier Science
Year
1972
Tongue
French
Weight
213 KB
Volume
13
Category
Article
ISSN
0040-4039

No coin nor oath required. For personal study only.

✦ Synopsis

In a recent paper Clementi and Marino treated substituent effect data for trifluoroacetylation of 2-substituted furans, thiophenes, and pyrroles by correlation with c+ 2 P in the Hammett equation. The magnitudes cf p values obtained were discussed as being related to differences in positions of the transition states along the reaction coordinates. We report here evidence which suggests that the variation in p values for different aromatic substrates is closely related to differences between the substrates in the distribution of charge developed in the transition state. uur proposal of this relationship is based on data from our studies of substituent effects in the solvolysis of heteroaryl derivatives and on results from CNDO/2 molecular orbital calculations.

Several recent investigations 3,4 have demonstrated that equations which take into account variations in the balance of field and resonance effects describe aromatic substituent effects more accurately than the simple use of substituent constants, such as u i, defined from the benzene series. However, satis-

📜 SIMILAR VOLUMES

Transmission of substituent effects in h
Transmission of substituent effects in heterocyclic systems. The correlation and prediction of solvolysis rates for heteroarylmethyl derivatives.
✍ Donald S. Noyce; Richard W. Nichols 📂 Article 📅 1972 🏛 Elsevier Science 🌐 French ⚖ 213 KB

Recent studies indicate a renewed interest in the mode of interaction of substituents with reaction sites in heterocyclic systems. 3,4 We have investigated this question further through use of the solvolysis reaction: a very useful reaction in this respect, as it shows high sensitivity to resonance

Ion-pair effects in electrochemistry of
Ion-pair effects in electrochemistry of aromatic compounds. The influence of supporting electrolyte cations on the ρπ constant of Hammett's equation
✍ M.K. Kalinowski 📂 Article 📅 1971 🏛 Elsevier Science 🌐 English ⚖ 289 KB

Half-wave potentials of p-substituted nitrobenzenes and benzaldehydes in dimethylformamide depend on the ionic potential $J of the cations of the electrolyte. For a series of compounds the Hammett's reaction constant, plr, is found to be a linear function of 6. This function is derived from the know

Heterophase N-Aminomethylation of 5-Aryl
Heterophase N-Aminomethylation of 5-Arylidenepseudothiohydantoins by Arylamines and Aqueous Formaldehyde in Aromatic Solvents: Effect of Substituents in the Heterocyclic Substrate and the Aryl Amine on the Efficiency of the Process.
✍ S. M. Ramsh; N. L. Medvedskiy; S. O. Uryupov 📂 Article 📅 2007 🏛 John Wiley and Sons ⚖ 19 KB

## Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.