Poly chiral amino acids containing

The molar ellipticity of these dendrimers was found to increase proportional to the number of chiral end groups. This is to be expected, in the absence of interactions between the terminal tryptophane moieties. No higher-generation dendrimers of this type have been reported. Other amino-acid-containing chiral dendrimers have been described by Meijer et al. who attached various amino acid derivatives to the periphery of poly(propylene imine) dendrimers (see Sect. 3) and more recently by Liskamp et al. (modification of polyamide dendra) [22] and Ritter et al. (synthesis of grafted polymerizable dendrimers containing L-aspartic acid components) [23]. 

NBD-amino acids (serine, threonine, valanie, phenylalanine, and histidine) were separated by using a 20 mM ammonium acetate buffer (pH 9.0) containing 10 mM copper acetate, 20 mM L-prolinamide, and 1 mM SDS. The elution order was the L-enantiomer followed by the D-form except in NBD-histidine. Weng et al. [32] described chiral separation of tryptophan on a poly(methyl methacrylate) microfluidic chip coated with bovine serum albumin (32 mm... 

D-and L-Poly(lysine) both occur in a helical conformation in aqueous solution above pH 10. A 1 1 mixture of both helices in water precipitates in the form of regular, silk-like P-sheets (Fig. 9.5.3). This is a polypeptide example of the chiral bilayer effect. It demonstrates the importance of chiral uniformity not only for noncovalent, soft-membrane systems, but also for covalent polyamides. Helical fibers in aqueous gels do not survive the addition of enantiomeric fibers with the single exception of DNA (see Fig. 8.6.1). The precipitation of enantiomeric peptides containing more than one kind of amino acid has, however, not been reported so far. 

S. Mallakpour, F. Zeraatpisheh, Pseudo-poly(amino acid)s study on construction and characterization of novel chiral and thermally stable nanostructured poly(ester-imide)s containing different trimellitylimi-do-amino acid-based diacids and pyromellitoyl-tyrosine-based diol. Colloid Polym. Sci. 289 (2011) 1055-1064. 

Mallakpour S, Zarei M. Novel, thermally stable and chiral poly(amide-imide)s derived from a new diamine containing pyridine ring and various amino acid-based diacids fabrication and characterization. High Perform Polym 2013 25(3) 245-53. 

Mallakpour S, Dinar M. Surface treated montmorillonite structural and thermal properties of chiral poly(amide-imide)/organoclay bionanocomposites containing natural amino acids. J Inorg Organomet Polym Mater 2012 22(5) 929-37. 

Another elegant example of the imitation of the properties of biopolymers by synthetic polymers comes from the school of E. Bayer of Tubingen (172). They have prepared chiral polysiloxane polymers for resolution of optical antipodes. The prochiral polymeric backbone was a copolymer of poly [(2-carboxypropyl)methylsiloxane], octamethylcyclotetrasiloxane, and hexa-methyldisiloxane. Amino acids or small peptides were covalently linked to this polymer in order to introduce a chiral surface. For this, the free carboxyl function of the polymer was reacted with the L-amino acid in the presence of DCC (see Chapter 2). The individual chiral centers (amino acids) on the polymer surface were separated by siloxane chains of specified length in order to achieve optimum interaction with the substrate and polymer viscosity. An example of great value for optical resolution is the polymer designated chirasil-Val, containing 0.86 mmole of iV-tert-butyl-L-valin-amide per gram of polymer (Fig. 5.14). 

Mallakpour, S., Dinari, M., 2013. Chiral hio-nanocomposites based on thermaUy stable poly(amide-imide) having phenylalanine Unkages and reactive organoclay containing tyrosine amino acid. Amino Acids 44, 1021—1029. 

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