Poly ordered polymer synthesis

The preparation of helically well-ordered polymers with stable screw-sense, which is able to be transmitted to newly formed polymer main-chains effectively, is highly desired for the development of new methodology for the synthesis of optically active helical polymers. An aromatizing polymerization of 1,2-diisocyanobenzenes is promoted by methylpalladium(II) complexes, producing poly(quinoxaline-2,3-diyl)s.146-148 The polymerization proceeds with successive insertion of the two isocyano groups of the diisocyanobenzene to the carbon palladium bond of... 

Yu SM, Soto CM, Tirrell DA (2000) Nanometer-scale smectic ordering of genetically engineered rodlike polymers synthesis and characterization of monodisperse derivatives of poly(y-benzyl a, L-glutamate). J Am Chem Soc 122 6552-6559... 

Synthesis of 2-Phenylallyl-ended Poly(a-methylstyrene). Synthesis of poly(a-methylstyrene) having an end double bond was described in our previous papers(15,16). Briefly, to the reactor (100 mL flask equipped with three-way stopcock), THF (6.6 mL), sec-butyllithium (0.34 mL 0.26 mmol) and a-methylstyrene (1.18 g 10 mmol) were added in this order via a syringe at -78 C. The color of the mixture turned brownish red immediately. The reaction was allowed to continue for 20 min. For an end-modification reaction, a 2-5 times excess molar amount of the end coupling agent, 2-phenylallyl bromide, was added to the living polymer solution and allowed to react for 20 min. The resulting mixture was analyzed by GPC and then poured into a large excess of methanol. The precipitate was purified by three successive reprecipitations from THF solution into methanol. The obtained polymer was freeze-dried with benzene to remove the solvents employed. Yield of the polymer was ca. 95%. 

Most abbreviations are based on the form poly(monomer) , i.e. on the names of the monomers used in polymer synthesis, often with the prefix P for poly . In case of copolymers, the monomers are given in alphabetic order. Some abbreviations also catch structural features or physical properties. ... 

Recently, we succeeded on the synthesis of ordered(-abcd-) poly(amide-thioether) by poly(addition-direct condensation) of a pair of two nonsynunetric monomers, 4-(actyloxy)benzoic acid (XabX) and 4-aminobenzenethiol (YcdY), where a polyaddtion was combined with a polycondensation to prepare the ordered polymer (4). Because, the selective amidation of carboxylic acids would be difficult using condensing agents due to the small difference of pKa values between carboxylic acids. An active ester is also useful as a substitute for a carboxylic acid component. 

It was therefore particularly inteipesting to investiage whether it would be possible to replace BPA by various derivatives of L-tyrosine as monomeric building blocks for the synthesis of poly-(iminocarbonates). In order to be practically useful in drug delivery applications, the replacement of BPA by derivatives of tyrosine must give rise to mechanically strong yet fully biocompatible polymers. 

The synthesis of poly(isothianapthene) (PITN) is an example of the second generation of conducting polymers, which have been prepared in order to produce a material with specific properties. Given the two inequivalent structures of polythiophene which give... 

Production of poly(3HB-co-3HV) co-polymer in plants has recently been demonstrated by the PHA group of Monsanto [27], which acquired the PHA business of Zeneca in 1996. In the commercial production of poly(3HB-co-3HV) from R. eutropha, propionate is added to the growth media in order to create an intracellular pool of propionyl-CoA which can be condensed to acetyl-CoA to form 3-ketovaleryl-CoA. The 3-ketovaleryl-CoA is then reduced by the aceto-acetyl-CoA reductase to give 3-hydroxyvaleryl-CoA, which is co-polymerized with 3-hydroxybutyryl-CoA to synthesize poly(3HB-co-3HV) (Fig. 1). For the synthesis of poly(3HB-co-3HV) in plants, it was thus necessary to create an endogenous pool of propionyl-CoA which could be used by the PHA pathway. 

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