Chlorine‐Atom Transfer Reactions between Chloramine (=Chloramide) and Piperidine: Kinetic Reactivity and Characterization in a Raschig Medium

Abstract

The kinetics of the Cl-transfer reaction between chloramine (1) and piperidine (2) in a Raschig medium (8 < pH < 9) was studied at various temperatures, with variable concentrations of the two reactants. The influence of the pH on the interaction of 1 and 2 was examined at a pH ranging between 8.25 and 12.89. The Cl-transfer reaction resulted in the formation of 1-chloropiperidine (3), which, in the presence of NaOH, underwent a dehydrohalogenation leading to an endocyclic imine derivative: 2,3,4,5-tetrahydropyridine (4). The kinetics of the dehydrohalogenation was also studied at different temperatures, with variable concentrations of 3 and NaOH. Kinetic and thermodynamic parameters were determined for the Cl-transfer and dehydrohalogenation reactions. Both 3 and 4 were prepared according to efficient synthetic routes; they were isolated, purified, and characterized by elemental analysis, IR, 1 H-and 13 C-NMR, and MS. Their thermal stabilities were evaluated by differential scanning calorimetry (DSC), and their absorption coefficients at various wavelengths were determined experimentally by UV spectrophotometry.

Biomimetic Organocatalytic Asymmetric Synthesis of 2-Substituted Piperidine-Type Alkaloids and Their Analogues

“…We prepared Δ 1 -piperideine 5a (via piperidine N -chlorination and base-mediated HCl elimination) and employed this electrophile in the reaction with carbonyl compounds 9a – b (see Table , entries 1–2).…”

Base-catalyzed reactions of environmentally relevant N-chloro-piperidines. A quantum-chemical study

“…35 We have successfully reproduced this experimental result by using highlevel computational models. The energy barrier of 87.0 kJ mol -1 (G3B3(+) + DG solv ) is calculated when base-catalyzed reaction between N-Cl-piperidine and hydroxide ion was considered (Scheme 4).…”

“…For example, 0.2 mM N-chloropiperidine in pH 10 borate buffer decreased only 3% over 24 h at 30 • C. 41 Recently it was found that the energy barrier for dehydrochlorination of N-Cl-piperidine in alkaline aqueous media is DH # (298.15 K) = 90.9 kJ mol -1 . 35 We have successfully reproduced this experimental result by using highlevel computational models. The energy barrier of 87.0 kJ mol -1 (G3B3(+) + DG solv ) is calculated when base-catalyzed reaction between N-Cl-piperidine and hydroxide ion was considered (Scheme 4).…”

“…Quantitative studies have, however, been performed on parent compound N-chloropiperidine (5-Cl) (Schemes 3 and 4). [32][33][34][35] Results and discussion…”

Kinetic modeling of the synthesis of N-aminopiperidine via the Raschig process: Reaction optimization and continuous process

“…Many side-reactions were identified and kinetically quantified, the most important of which are the oxidation of NAPP with chloramine [5] and the chlorineatom transfer reaction between chloramine and piperidine [6]. In this paper, we report our results on the elaboration of a kinetic model, which reflects the experimental results of the main and side-reactions occurring during NAPP synthesis.…”