Can Non-bonded Pair of Electrons of Sp3 Nitrogen with Two Single σ-Bonds on Either Side Still Transmit Substituent Electronic Effects to the Reaction Site? Reversal of Attenuation Effect by Sp3 Nitrogen–A Chemical Education Perspective
Journal Title: Chemical Methodologies - Year 2020, Vol 4, Issue 1
Abstract
Dependence of reactivity of organic molecules on substituents was a well-established phenomenon in terms of Hammett and Taft equations in physical-organic chemistry. The well-known Hammett and Taft linear free energy relationships were extensively used in elucidating the organic reaction mechanisms. The exponential depletion of Hammett reaction constant (ρ), as a function of distance in terms of increasing the number of sp3 carbon atoms (-CH2-) between the reaction center and the substituent, is understood from our laboratory experiments. But, introduction of sp2 carbon atoms (-CH=CH-) between the reaction center and the substituent enhances the Hammett reaction constant (ρ). In the present work, we have tried and observed the same and even little more effective transmission of substituent effect through sp3 nitrogen (-NH-). However, the presence of a sp3 carbon by the side of sp3 nitrogen (-NH-CH2-) depletes the substituent effect in the usual manner in N-phenyl glycines. Probable explanations were presented in support of our observation. In the present work, the observations were manifested in terms of Taft ρ* values instead of Hammett ρ value as the pKa values of only 4-nitopheylcarbamic acid and carbamic acids and the Taft σ* values of 4-nitrophenyl and H are available from literature.
Authors and Affiliations
R. Sanjeev, V. Jagannadham
Keywords
Related Articles
- EP ID EP617357
- DOI 10.33945/SAMI/CHEMM.2020.1.10
- Views 70
- Downloads 0
Effects of Freeze-drying and Freezing on Vitamins and Sugars of Mango Pulp (‘Apple’ Cultivar): A Preliminary Comparison of Methods for Improving Sample Storage
Mango (Mangifera indica L.) fruits are highly perishable ones whose important nutrients such as vitamins and sugars quickly decrease under storage. In this study, we compared two methods of fruit pulp storage; freezing a...
Estimation of Anti-dengue Phytochemical Markers Gallic acid, Rutin and Quercetin in Methanolic Extract of Euphorbia hirta (L.) and Tawa-Tawa Capsule Formulation by Validated RP-HPLC Method
Sensitive and precise RP-HPLC method with photo diode array detector has been developed and validated for the simultaneous estimation of three commonly available anti-dengue, anti-cancer and anti-inflammatory phytochemic...
Effect of Trimethoprim Inclusion Complexation with Cyclodextrins on its Antimicrobial Activity
The aim of present study is to highlight the effects of β-cyclodextrin (BCD) and hydroxypropyl-β-cyclodextrin (HBCD) and also the effect of their concentrations and methods of inclusion complexation on solubility and ant...
One pot Facile Synthesis of Anti-microbial β-Lactam Derivatives Catalysed by Fe(acac)3
We have developed novel route for the synthesis of β-Lactam by Fe(acac)3 based catalytic system with >90% yield. It is one pot Knoevenagel condensation of aldehyde with ethyl cyanoacetate followed by chemoselective reduc...
N1,N1,N2,N2-Tetramethylethylenediaminium-N1,N2-disulfonic Acid Trifluoroacetate as Highly Effectual and Dual-Functional Catalyst for the Reaction of β-Ketoesters with Aryl Aldehydes and Urea/Thiourea
In this research, the one-pot multi-component reaction of β-ketoesters with aryl aldehydes and urea/thiourea has been performed using a dual-functional ionic liquid-catalyst namely N1,N1,N2,N2-tetramethylethylenediaminiu...