1516-27-4Relevant articles and documents
Synthetic approach for unsaturated precursors for parahydrogen induced polarization of choline and its analogs
Shchepin, Roman V.,Chekmenev, Eduard Y.
, p. 655 - 662 (2013)
Reported here are (i) a new synthetic approach for preparation of (ii) a new compound class, of -OH, for example, an -OH group is replaced with acetyl protecting group, protected 1,2-dehydrocholine analogs and (iii) a new synthetic route for betaine aldehyde. The C=C bond of 1,2-dehydrocholine moiety can be used for molecular addition of parahydrogen producing -OH protected hyperpolarized choline by parahydrogen-induced polarization (PHIP). The reported synthetic approach allows for incorporation of 15N and deuterium labels, which are necessary for preparation of highly polarized PHIP contrast agents. Isotope labeling with 15N and/or deuterium was conducted. Hyperpolarized 15N-choline enabled by the reported synthetic approach can be potentially used as an imaging biomarker of cancer similar to choline positron emission tomography tracers. Copyright
A novel composite nanofiltration (NF) membrane prepared from graft copolymer of trimethylallyl ammonium chloride onto chitosan (GCTACC)/poly(acrylonitrile) (PAN) by epichlorohydrin cross-linking
Huang, Ruihua,Chen, Guohua,Sun, Mingkun,Gao, Congjie
, p. 2777 - 2784 (2006)
A novel composite nanofiltration (NF) membrane was prepared by over-coating the PAN ultrafiltration (UF) membrane with a GCTACC thin layer. The effects of membrane preparation techniques and operating conditions on the performance of the composite membrane were studied. The results indicate that a composite NF membrane from 1.0 wt % GCTACC casting solution, vaporized for 2 h at 50 °C, cross-linked for 20 h at 50 °C and pH ≈ 12 with ethanol/epichlorohydrin (50/0.45 wt/wt) had optimum performance. The resultant GCTACC/PAN composite membrane was positively charged. Scanning electron microscopy showed its asymmetric and composite features. At 25 °C and 30 L/h of cycling flow, the permeability of pure water through this membrane is 6.3 L/h m2 MPa. At 25 °C, 1.2 MPa and 30 L/h of cycling flow, the rejection of 1000 mg/L MgCl2, CaCl2, MgSO4, Na2SO4, and NaCl solutions is 0.976, 0.972, 0.897, 0.65, and 0.407, respectively, with fluxes of 6.8, 6.12, 6.12, 5.57, and 5.51 L/h m2, respectively. The order of rejection of different salts follows the decreasing order of MgCl2, CaCl2, MgSO4, NaCl, KCl, Na2SO4, and K2SO4, which reveals the characteristics of the positively charged NF membrane. In addition, the curve for the streaming potential also illustrates the positively charged characteristics of this membrane, with a pressure osmotic coefficient of 11.7 mV MPa-1.
Site-Selective Installation of N?-Modified Sidechains into Peptide and Protein Scaffolds via Visible-Light-Mediated Desulfurative C–C Bond Formation
Griffiths, Rhys C.,Layfield, Robert,Long, Jed E.,Mitchell, Nicholas J.,Oldham, Neil J.,Scott, Daniel,Smith, Frances R.,Williams, Huw E. L.
supporting information, (2021/12/08)
Post-translational modifications (PTMs) enhance the repertoire of protein function and mediate or influence the activity of many cellular processes. The preparation of site-specifically and homogeneously modified proteins, to apply as tools to understand the biological role of PTMs, is a challenging task. Herein, we describe a visible-light-mediated desulfurative C(sp3)–C(sp3) bond forming reaction that enables the site-selective installation of N?-modified sidechains into peptides and proteins of interest. Rapid, operationally simple, and tolerant to ambient atmosphere, we demonstrate the installation of a range of lysine (Lys) PTMs into model peptide systems and showcase the potential of this technology by site-selectively installing an N?Ac sidechain into recombinantly expressed ubiquitin (Ub).
Olefin cross-metathesis on proteins: Investigation of allylic chalcogen effects and guiding principles in metathesis partner selection
Lin, Yuya A.,Chalker, Justin M.,Davis, Benjamin G.
supporting information; experimental part, p. 16805 - 16811 (2011/02/17)
Olefin metathesis has recently emerged as a viable reaction for chemical protein modification. The scope and limitations of olefin metathesis in bioconjugation, however, remain unclear. Herein we report an assessment of various factors that contribute to productive cross-metathesis on protein substrates. Sterics, substrate scope, and linker selection are all considered. It was discovered during this investigation that allyl chalcogenides generally enhance the rate of alkene metathesis reactions. Allyl selenides were found to be exceptionally reactive olefin metathesis substrates, enabling a broad range of protein modifications not previously possible. The principles considered in this report are important not only for expanding the repertoire of bioconjugation but also for the application of olefin metathesis in general synthetic endeavors.
