A sorbent based on affinity ionic liquid (AIL), triazacyclononane-ionic liquid, was synthesized, characterized, and applied to the extraction of histidine (His)-tagged proteins from aqueous buffer to ionic liquid (IL) phase. The adsorbed His-tagged proteins could be back-extracted from the IL phase to the aqueous buffer with an imidazole solution. The specific binding of His-tagged proteins with AIL/IL could be affected by a few factors including the ionic strength and coordinated metal ions. In the case of His-tagged enhanced green fluorescent protein (EGFP), the maximum binding capacity of Cu(2+)-AIL/IL reached 2.58 μg/μmol under the optimized adsorption conditions. The eluted His-tagged EGFP kept fluorescent and remained active through the purification process. Moreover, a tandem extraction process successively using Cu(2+)-AIL/IL and Zn(2+)-AIL/IL systems was developed, which was proven very efficient to obtain the ultimate protein with a purity of about 90 %. An effective reclamation method for the AIL/IL extraction system was further established. The sorbent could be easily regenerated by removing metal ions with EDTA and the followed reimmobilization of metal ions. Easy handling of the presented M(2+)-AIL/IL system and highly specific ability to absorb His-tagged proteins make it attractive and potentially applicable in biomolecular separation.

The misfolding and fibrillization of β amyloid (Aβ) is a major pathological hallmark of Alzheimer’s disease (AD) and creates an important niche for developing targeted probe and drug designs. Phthalocyanine...

Affinity adsorption purification of hexahistidine-tagged (His-tagged) proteins using EDTA-chitosan-based adsorption was designed and carried out. Chitosan was elaborated with ethylenediaminetetraacetic acid (EDTA), and the resulting polymer was characterized by FTIR, TGA, and TEM. Different metals including Ni(2+), Cu(2+), and Zn(2+) were immobilized with EDTA-chitosan, and their capability to the specific adsorption of His-tagged proteins were then investigated. The results showed that Ni(2+)-EDTA-chitosan and Zn(2+)-EDTA-chitosan had high affinity toward the His-tagged proteins, thus isolating them from protein mixture. The target fluorescent-labeled hexahistidine protein remained its fluorescent characteristic throughout the purification procedure when Zn(2+)-EDTA-chitosan was used as a sorbent, wherein the real-time monitor was performed to examine the immigration of fluorescent-labeled His-tagged protein. Comparatively, Zn(2+)-EDTA-chitosan showed more specific binding ability for the target protein, but with less binding capacity. It was further proved that this purification system could be recovered and reused at least for 5 times and could run on large scales. The presented M(2+)-EDTA-chitosan system, with the capability to specifically bind His-tagged proteins, make the purification of His-tagged proteins easy to handle, leaving out fussy preliminary treatment, and with the possibility of continuous processing and a reduction in operational cost in relation to the costs of conventional processes.

Piperazine derivatives are important intermediates in organic synthesis and useful building blocks in pharmaceutical and fine chemical industries. Currently available synthetic routes for these heterocyclic compounds have limited scope owing to the harsh reaction conditions, low yields, and multistep process. Herein, we reported a practical method for synthesis of alkyl-, alcohol-, amine-, and ester-extended tosylpiperazines under mild conditions with moderate to high yields. This protocol exhibits potential applicability in the synthesis of pharmaceuticals and natural products because of the operational simplicity and the conveniently available reactants. On the basis of the experimental and theoretical results, a plausible mechanism of aliphatic nucleophilic substitution (S(N)) in the cyclization has been postulated and evidence for the formation of a six-membered ring has also been confirmed by means of density functional theory (DFT) calculations.

The novel synthesis of task-specific ionic liquids (TSILs) introducing piperazine substructures was described. Piperazine functional groups were easily grafted onto an imidazolium cationic derivative via a simple four-step process starting from available materials such as imidazole, ethylene glycol, and 1-butylamine or 3-dimethylaminopropylamine. Effects of pH, temperature, and structure of functional groups on the performance of liquid-liquid extraction of Cu 2þ , Ni 2þ , and Co 2þ from water were investigated. It was found that TSILs were efficient for removal of these metal ions in mild acid solutions. The TSIL with an extra nitrogen atom showed a higher capability to separate metal ions, especially for Cu 2þ . This may be ascribed to the intrinsic structure of the functional groups -the more coordination sites, the higher the affinity for the metal ions. Furthermore, the thermodynamics indicated that the extraction process was exothermic and spontaneous in nature.

Base‐mediated treatment of the protected amino alcohol (I) with amines results in mild and convenient formation of a number of N≈‐alkylated tosylpiperazines including heteroalkyl‐substituted ones.