1. High-Quality Conjugated Polymers Achieving Ultra-Trace Detection of Cr2O72- in Agricultural Products
Hui Li, Fei Li, Fang Liu, Xiao Chen, Wenyuan Xu, Liang Shen, Jingkun Xu, Rui Yang, Ge Zhang Molecules. 2022 Jul 4;27(13):4294. doi: 10.3390/molecules27134294.
In view of that conjugated polymers (CPs) are an attractive option for constructing high-sensitive Cr2O72- sensors but suffer from lacking a general design strategy, we first proposed a rational structure design of CPs to tailor their sensing properties while validating the structure-to-performance correlation. Short side chains decorated with N and O atoms as recognition groups were instructed into fluorene to obtain monomers Fmoc-Ala-OH and Fmoc-Thr-OH. Additionally, their polymers P(Fmoc-Ala-OH) and P(Fmoc-Thr-OH) were obtained through electrochemical polymerization. P(Fmoc-Ala-OH) and P(Fmoc-Thr-OH) with high polymerization degrees have an excellent selectivity towards Cr2O72- in comparison to other cations and anions. Additionally, their limit of detection could achieve 1.98 fM and 3.72 fM, respectively. Especially, they could realize the trace detection of Cr2O72- in agricultural products (red bean, black bean, and millet). All these results indicate that short side chains decorated with N and O atoms functionalizing polyfluorene enables the ultra-trace detection of Cr2O72-. Additionally, the design strategy will spark new ideas for the construction of highly selective and sensitive Cr2O72- sensors.
2. Design and synthesis of Fmoc-Thr[PO(OH)(OPOM)] for the preparation of peptide prodrugs containing phosphothreonine in fully protected form
Wen-Jian Qian, Christopher C Lai, James A Kelley, Terrence R Burke Jr Chem Biodivers. 2014 May;11(5):784-91. doi: 10.1002/cbdv.201300202.
The design and efficient synthesis of N-Fmoc-phosphothreonine protected by a mono-(pivaloyloxy)methyl (POM) moiety at its phosphoryl group (Fmoc-Thr[PO(OH)(OPOM)]-OH, 1, is reported. This reagent is suitable for solid-phase syntheses employing acid-labile resins and Fmoc-based protocols. It allows the preparation of phosphothreonine (pThr)-containing peptides bearing bis-POM-phosphoryl protection. The methodology allows the first reported synthesis of pThr-containing polypeptides having bioreversible prodrug protection, and as such it should be useful in a variety of biological applications.
3. Total Synthesis of Alloviroidin
Carol M Taylor, Samuel K Kutty, Benson J Edagwa Org Lett. 2019 Apr 5;21(7):2281-2284. doi: 10.1021/acs.orglett.9b00567. Epub 2019 Mar 12.
Alloviroidin is a cyclic heptapeptide, produced by several species of Amanita mushrooms, that demonstrates high affinity for F-actin as is characteristic of virotoxins and phallotoxins. Alloviroidin was synthesized via a [3 + 4] fragment condensation of Fmoc-d-Thr(OTBS)-d-Ser(OTBS)-(2 S,3 R,4 R)-DHPro(OTBS)2-OH and H-Ala-Trp(2-SO2Me)-(2 S,4 S)-DHLeu(5-OTBS)-Val-OMe to form bond A. The linear heptapeptide favored a turn conformation, facilitating cyclization between Val1 and d-Thr2 (position B). Global deprotection and HPLC purification afforded alloviroidin with NMR spectra in excellent agreement with the natural product.
