Long-Chained Pyridinium

Abstract

Two types of long-chained pyridinium N-chloramines were designed and synthesised by covalent linking a N-chloramine unit and a long intact alkyl chain via varied alkylation of 3-hydroxypyridine. Preliminary antibacterial tests showed that both synthetic pyridinium N-chloramines exerted distinctively elevated biocidal efficacy in contrast to previously reported pyridinium N-chloramines that lack a long chain. Such enhanced bactericidal behaviour was probably caused by ‘synergistic’ biocidal action between the N-chloramine moiety and the long-chained pyridinium moiety.

New cationic linear N-chloramines based on N-t-butylamide: chemical synthesis and antibacterial application

“…The highlight of the synthesis route based on 21 is the elevated total yield (from 20% to 60%) as well as the overall simplified procedure without ion exchange. 9–12 Such observations (including 13 C NMR spectra in Fig. S5, ESI†) together with HRMS data, evidently implied the successful chlorination.…”

“…S1, ESI†). According to previous reports, 9–13 the electron-withdrawing inductive (EWI) effect of the new N–Cl bond causes a specific downfield chemical shift, obvious in the NMR spectra. For instance, the –CH 3 signal shifted downfield from 1.28 ppm to 1.45 ppm, and the –CH 2 – signal shifted downfield from 3.91 ppm to 4.50 ppm (Fig.…”

“…To address the issue of aqueous solubility of DMH-based N -chloramines, which suppresses biocidal efficacy, 8 we recently developed ionic N -chloramines (Fig. 1), including typical representatives of QA 1 , 9 pyridinium 2 , 10 QP 3 , 11 sulfonium 4 , 12 and zwitterion 5 . 13 It was proved that the ionic centre not only improved the aqueous solubility, but drastically enhanced the biocidal efficacy of the N–Cl moiety as well.…”

“…16 After treating with aqueous Et 3 N in EtOH under reflux, amide 6a (Br − form) was obtained. After anion exchange, transformation from 6a (Cl − form) to 6 by means of t -BuOCl chlorination 9–13 was surprisingly incomplete based on NMR data analysis (Fig. S1, ESI†).…”

Quaternary Ammonium (QA) N‐Chloramines: Chemical Synthesis and Study on Structure Bactericidal Activity Relationship

“…As expected, 21 realized total kill of S. aureus and E. coli within 5 minutes, indicating the best antibacterial performance of this serie. Based on superior bactericidal efficacy of long-chained sulfonium N-chloramines and long-chained pyridinium Nchloramines, [9,15] it could be preliminarily concluded that the presence of an structral intact long chain (e. g. À C 12 H 25 ) is indispensable for the highly efficacious biocidal performance due to "synergistic" antibacterial actions between the two respective bacteriacidal units of N-Cl scaffold and QA salt moiety. Given that the specific charge remains constant (Figure 1, m + n = 13) and that the methylene linker length ChemistrySelect increases (n increases), the length of intact chain essentially decreases (m decreases).…”