Amines as leaving groups in nucleophilic aromatic substitution reactions. Part 4.1 σ-Adduct formation in the hydrolysis of 1-amino-2,4,6-trinitrobenzenes

Abstract

The kinetic study of the reaction of 2,4,6-trinitro-1-pyrrolidinobenzene 3, 2,4,6-trinitro-1-piperidinobenzene 1 and 1-morpholino-2,4,6-trinitrobenzene 2 was made in 1,4-dioxane-water mixtures at 25 ЊC. In all cases, several processes were observed, the slowest of them leading to the formation of picrate ion. The fastest processes involved the formation of σ complexes by addition of one or two HO Ϫ to unsubstituted ring positions and the ionisation of the 1 : 1 complex. Besides, for compounds 1 and 3, cis-trans isomerisation of 1 : 2 complexes was kinetically detected. Substitution occurred by displacement of the amino group on the substrate and the 1 : 1 complex. The reaction pathway for the formation of phenol which involves the formation of these complexes has lower energy than that which results from addition to the 1 position of the substrate.

Amines as leaving groups in nucleophilic aromatic substitution reactions. Part 5.1 Substitution vs. N-oxide formation in the reaction of N-n-butyl-2,6-dinitroaniline with hydroxide ions

“…7 We have demonstrated that in aqueous solutions cyclic amines like pyrrolidine, piperidine and morpholine can act as leaving groups in aromatic nucleophilic substitution reactions of 1-amino-2,4-dinitrobenzenes, 8 and 1-amino-2,4,6-trinitrobenzenes. 1,9 Imidazole can also act as a leaving group in a reaction with hydroxide ions, 10 and n-butylamine 11 from 2,4,6-trinitrobenzene derivatives and piperidine and n-butylamine from 2,4-dinitrobenzene derivatives. 12 In this paper we report on the kinetics of the reaction of N-n-butyl-2,6-dinitroaniline 1 in basic solution which, in addition to the substitution product of the alkyl amino group, 2,6-dinitrophenol 2, gives a cyclization product, namely 7-nitro-2-n-propyl-1H-benzimidazole 3-oxide 3.…”

On the Stability and Degradation Pathways of Venetoclax under Stress Conditions

“…The second key degradation pathway in basic conditions is a nucleophilic aromatic substitution (S N Ar) of the 2-nitro-substituted benzene with the hydroxyl group from NaOH [ 50 , 54 , 58 , 59 , 60 ], resulting in degradation product B2 ( 7 ).…”

Synthesis of Energetic Polymers by the Introduction of Energetic Groups onto Polymeric Primary and Secondary Amines

“…In order to have an alternative way of measuring the degree of substitution by picryl groups in polyethylenimine, we investigated the possibility of hydrolytically removing the picryl groups and measuring the amount of picric acid liberated [11]. Preliminary experiments with N-picryldiethylamine showed that it was only hydrolysed under basic conditions.…”