We developed a continuous flow system using ω-transaminase covalently immobilized on an epoxy resin modified with ethylenediamine (EDA) to synthesize (S)-1-Boc-3-aminopiperidine, which is a key intermediate for several novel inhibitors. A second functional group (−NH3+) was introduced to rapidly adsorb ω-transaminase, which was further rigidified by multipoint covalent attachment to the modified resin with high binding efficiency (>95%) and activity recovery (75%). The resulting immobilized ω-transaminase was stable with 90% residual activity after 15 reuse cycles. We synthesized (S)-1-Boc-3-aminopiperidine using this continuous flow system, and 95% conversion was obtained within 10 min of residence. The system was continuously operated for 24 h and achieved a space–time yield of 930.73 g·L–1·day–1, indicating outstanding reaction efficiency. This efficient continuous bioprocess has potential for large-scale production of (S)-1-Boc-3-aminopiperidine.
Aiwen Zhang,Junyong Zhu,Shuangqiao Han,Yatao Zhang,Bart Van der Bruggen
Low-pressure nanofiltration (NF) has evinced huge application prospects for ion/molecule separation. However, current polyamide-based membranes made by highly reactive monomers offer less control in precisely tuning of their pore apertures, leading to a permeability-selectivity trade-off limit. Herein, the usage of amino-piperidine (AP, 4-aminopiperidine: 4AP; 3-aminoapiperidine: 3AP) is proposed as new building block that interfacially polymerizes with trimesoyl chlorides (TMC) onto a nanofibrous hydrogel to fabricate high-performance thin film composite (TFC) membranes. The resultant amino-piperidine thin film composite (AP-TFC) membranes with nodular and bubble-like surface have high hydrophilicity, electronegativity, and moderate crosslinking degree. Introducing an alkane bond length based on the piperidine structure allows to finely augment the free-volume elements of polyamide-based membranes, combined with varying the monomer concentrations. Furthermore, the 4AP-TFC membranes showed an excellent water permeability of 35.0 L m −2 h −1 bar −1 with Na 2 SO 4 rejection above 98.5% when the 4AP concentration was 0.05 w/v%. The 4AP-TFC membrane was also found having a superior sieving capability for antibiotics, attributed to the synergy of size exclusion by well-defined ultra-microporous structure (<0.7 nm) and electrostatic repulsion due to the abundance of surface negative charges. This work provides the guideline of using AP molecules for the fabrication of high-crosslinked TFC membranes with potential applications in low-pressure NF, organic solvent NF, and related water purification .
In this study, we present an improved metabolomics methodological framework that synergistically integrates untargeted data acquisition with targeted data analysis using chemical derivatization combined with ultrahigh performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF MS) analysis. Data-independent acquisition (DIA)-based mass spectrometry (MS1) data were used to conduct conventional untargeted analysis for biomarker discovery. The data-dependent acquisition (DDA) method was applied to obtain high-quality tandem mass spectrometry (MS2) information for quantitative data analysis. 1-Aminopiperidine (1AP) served as the derivatization reagent for sample preparation, which selectively reacts with carboxyl-containing compounds. Fatty acid (FA) standards were used to examine the derivatization reaction, and the results of LC-MS analysis showed that protonated FA + 1AP-H2O was the precursor. The ion at m/z 84.08, along with the product ion from a neutral loss of 45.02 Da, emerged as characteristic fragments, facilitating compound annotation and quantitative analysis. Method validation results demonstrated the proposed method with excellent repeatability, stability, and linearity. The lung tissue samples were successfully analyzed using this method, which was further employed to evaluate the therapeutic efficacy of Zhuye Shigao Decoction (ZSD) against lipopolysaccharide (LPS)-induced acute pneumonia in mice.
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