Glycopeptides modified glycopeptide

The macrocyclic glycopeptides CSPs arc capable of operating in three different mobile phase systems reversed phase, normal phase, and the new polar organic mode. The new polar organic mode refers to the approach when methanol is used as the mobile phase with small amounts of acid and/or base as the modifier to control... 

All these chemically modified glycopeptides have been helpful in understanding the mechanism of the chiral recognition process mediated by these macrocycles. 

Carboxylic acid-terminated organosilanes were used in the early studies on chemically bonded glycopeptides to immobilize vancomycin and thiostrepton via then-amino groups, leading to the formation of stable amide bonds between antibiotics and modified silica [7]. In a typical reaction, 4 g of dry silica gel is slurried on 50 mL of dry toluene. Two grams of [l-(carbomethoxy)ethyl]methyldichlorosilane or [2-(carbomethoxy)ethyl]trichlorosilane is dissolved in 15 mL of dry toluene contained in a dropping flask. The organosilane solution is added dropwise over 30 min... 

NaCNBH3 (10 mM) in phosphate buffer (pH = 3). The slurry is sonicated for 1 h, centrifuged, and the cyanoborohydride solution eliminated. The modified silica is washed with water and methanol, and then dried. This chemistry of binding provided for vancomycin a substantial bonding density of 120 p,mol/g (0.40 p,mol/m ) [70] (see Table 2.2). Surface coverage data for ristocetin A [75] and glycopeptide MDL 63,246 [43,44] were not provided by the authors. 

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