Polyglycerol chain

Recently, Childs and Neuhaus41 described the in vitro acylation of polyglycerol phosphate chains with D-alanyl ester residues in a two-step reaction sequence. In the first step D-alanine is enzymatically transformed into an activated form, and in the second reaction the D-alanine molecule is incorporated into the LTA chain by a specific ligase. 

In this context, the chiral hyperbranched polyglycerols (-)-PG [Mn = 3000, with bis(2,3-dihydroxypropyl)undecenylamine as the initiator] and (+)-PG [Mn = 5500, with trimethylolpropane (TMP) as the initiator] were used. Esterification of the hydroxyl groups of these hyperbranched polyglycerols with hydrophobic alkyl chains as palmitoyl chloride, yielded amphiphilic molecular nanocapsules with reverse micelle-type architecture, in which approximately 50% of the hydroxyl groups were functionalized with palmitoyl chains [96-98]. These materials exhibit low polydispersity (Mw/Mn < 2), and the amphiphilic molecular nanocapsules are soluble in nonpolar solvents and irreversibly encapsulate various polar, water-soluble dye molecules in their hydrophilic interior by liquid-liquid extraction [96,98]. 

Babayan, V. K., and McIntyre, R. T. 1971. Preparation and properties of some polyglycerol esters of short and medium chain length fatty acids. /. Am. Oil Chem. Soc., 48, 307-309. 

The dominant contribution of simultaneous chain growth from all the chain ends, controlled by the deprotonation level of the initiator, leads to relatively narrow MWD B 1.1-1.4) while maintaining branching levels typical of random polycondensation reactions (degree of branching a 0.5, Eq. 30.7) [70]. The SCROP technique has also been used to synthesize hyperbranched polyglycerols [70], polyethers [71], and polyamines [72]. 

Figure 16 Illustration of the structural elements of PGPR. The upper stmcture is that of the polyricinoleate moiety the lower stmcture shows the polyglycerol hackhone. The R in the structure can be either hydrogen, a fatty acid residue, or a polyricinoleate residue. In PGPR at least one of the side chains is polyricinoleate.

Ishitobi, M., and Kunieda, H. (2000) Effect of distribution of hydrophilic chain on the phase behavior of polyglycerol fatty add ester in water. Colloid Polym. Sci., 278, 899-904. 

SCHEME 8.4 Schematic illustration of the processes involved in the graft copolymerization of DMAEMA from PVDF main chains via AGET-ATRP, preparation of PVDF-g-PDMAEMA membrane by phase inversion, and quaternization of PVDF-g-PDMAEMA membrane by propargyl bromide to produce PVDF-g-PQDMAEMA membrane with pendant aUcyne groups, covalent immobilization of hyperbranched polymer HPG-Nj or PEI-Nj onto the PVDF-g-PQDMAEMA membrane surface via surface alkyne-azide click reaction. PVDF, poly(vinylidene fluoride) DMAEMA, 2-(V, V-dimethylamino)ethyl methacrylate VC = L-ascorbic acid PMDETA = V,V,M,V, A"-pentamethyl diethylene triamine HPG-N3 = az/hyperbranched polyglycerols PEI-N3 = azirfo-polyethylenimine. Reprinted with permission from Reference 114. Copyright 2013 American Chemical Society. 

The polyglycerol phosphate chain of lipoteichoic acid is not synthesised from CDP-glycerol in the same way as the wall teichoic acids. The glycerol phosphate units are of the opposite stereochemical series to those found in... 

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