Kinetics of the reactions between 1,2-dinitrobenzene and aliphatic primary amines in benzene. A probable mechanism for the observed mild acceleration

An Original Electrochemical Pathway for the Synthesis of Porphyrin Oligomers

“…Similar rate accelerations due to the addition of small amounts of a HBA co‐solvent were found in the reactions of 1,2‐dinitrobenzene with butylamine in benzene. While the reaction is almost insensitive to other additives, the accelerations observed upon the addition of DMSO to benzene exceed expectations based only on considerations of the polarity of the medium,56 in line with the present finding for the reactions studied in toluene/DMSO binary solvents. To support this interpretation of the experimental results, theoretical semi‐empirical and ab initio calculations were performed to investigate the likelihood of 2‐GB: DMSO hydrogen bond formation.…”

S N Ar Reactions of Amines in Aprotic Solvents

“…This behaviour is characteristic of most base-catalysed reactions. On the other hand, whereas all the studied reactions were base-catalysed in n-hexane, only mild acceleration was observed in benzene 9 . Also, the reactions seem to be inhibited in benzene and other electron-donor solvents, and Silber and coworkers attributed this effect to a preferential solvation exerted through EDA complex formation with the aromatic substrate, as shown in Scheme 4 9 .…”

Unusual solvent effects in the reactions of 1-halo-2,4-dinitrobenzenes and aniline in aprotic and dipolar-aprotic solvents. Effects of aggregates

“…Similar rate accelerations due to the addition of small amounts of a HBA cosolvent were found in the reactions of 1,2-dinitrobenzene with butylamine in benzene. While the reaction is almost insensitive to other additives, the accelerations observed upon addition of DMSO to benzene exceed expectations based only on considerations of the polarity of the medium, 8,17 as the present finding for the reactions studied in toluene:Ac binary solvents.…”

“…4,5,6 The mechanisms of reactions in protic solvents are well established1 but are the S N Ar in aprotic solvents those that exhibit most peculiar features to study specific and non-specific solvent effects. 2 Evidences for nucleophile aggregation, 7 substrate-nucleophile EDA complexes 8 and other type of complexes 9,10 have been reported by different authors when reactions were carried out in aprotic solvents. On the other hand, several attempts to establish empirical scale of microscopic parameters able to provide a quantitative description of solvent characteristic have been currently reported.…”