26150-05-0Relevant articles and documents
Stereoselective Synthesis of Molecular Square and Granny Knots
Leigh, David A.,Pirvu, Lucian,Schaufelberger, Fredrik
, p. 6054 - 6059 (2019)
We report on the stereoselective synthesis of both molecular granny and square knots through the use of lanthanide-complexed overhand knots of specific handedness as three-crossing "entanglement synthons". The composite knots are assembled by combining two entanglement synthons (of the same chirality for a granny knot; of opposite handedness for a square knot) in three synthetic steps: first, a CuAAC reaction joins together one end of each overhand knot. Ring-closing olefin metathesis (RCM) then affords the closed-loop knot, locking the topology. This allows the lanthanide ions necessary for stabilizing the entangled conformation of the synthons to subsequently be removed. The composite knots were characterized by 1H and 13C NMR spectroscopy and mass spectrometry and the chirality of the knot stereoisomers compared by circular dichroism. The synthetic strategy of combining building blocks of defined stereochemistry (here overhand knots of λ- or Δ-handed entanglement) is reminiscent of the chiron approach of using minimalist chiral synthons in the stereoselective synthesis of molecules with multiple asymmetric centers.
Maki et al.
, p. 635 (1969)
A single-mercapto double-cetyl the ether gathers glycol [...] glycolipid synthesis method (by machine translation)
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Paragraph 0062-0065, (2019/11/04)
The invention discloses a single mercapto double-cetyl [...] glycol [...] glycolipid synthesis method, characterized in that the 2, 3, 4, 6 - O - acetyl - α - D - pyran mannose the heat stability of the polyurethane in the [...][...] benzoic acid with thr
Salt- and pH-Triggered Helix-Coil Transition of Ionic Polypeptides under Physiology Conditions
Yuan, Jingsong,Zhang, Yi,Sun, Yue,Cai, Zhicheng,Yang, Lijiang,Lu, Hua
, p. 2089 - 2097 (2018/06/15)
Controlling the helix-coil transition of polypeptides under physiological conditions is an attractive way toward smart functional materials. Here, we report the synthesis of a series of tertiary amine-functionalized ethylene glycol (EGx)-linked polypeptide electrolytes with their secondary structures tunable under physiological conditions. The resultant polymers, denoted as P(EGxDMA-Glu) (x = 1, 2, and 3), show excellent aqueous solubility (>20 mg/mL) regardless of their charge states. Unlike poly-l-lysine that can form a helix only at pH above 10, P(EGxDMA-Glu) undergo a pH-dependent helix-coil switch with their transition points within the physiological range (pH ～5.3-6.5). Meanwhile, P(EGxDMA-Glu) exhibit an unusual salt-induced helical conformation presumably owing to the unique properties of EGx linkers. Together, the current work highlights the importance of fine-tuning the linker chemistry in achieving conformation-switchable polypeptides and represents a facile approach toward stimuli-responsive biopolymers for advanced biological applications.
