Subject polymer-analogous reactions

Those not affecting DP. These involve reactions of functional groups already contained in the polymer molecules Some of these reactions are reversible and are referred to as polymer-analogous transformations. These reactions have been used in polymer-mediated organic syntheses and will be the subject of the bulk of this book. 

To initiate the first step of the repetitive synthesis, the trityl chloride derivative of polystyrene was subjected to reaction with thymidine in pyridine (Scheme 6). It is note-worthy that unreacted trityl chloride groups were blocked as methyl ethers by addition of methanol [41], The thymidine content was found to be 60-340 jumol g" after polymer-analogous cleavage from the support. This capacity corresponds to a degree of functionalization of 15-85% and points to steric problems of this attachment to the polymer. 

Each microreactor consists of a polymer-bound substrate and a radiofrequency encoded microchip enclosed within a small porous vessel. The radiofrequency tag allows the identity of the substrate contained within each microreactor to be established readily. Using this technology, the polymer-bound substrates 86 were individually elaborated, within separate microreactors, by sequential reactions with acids 87 and alcohols 88 in a similar way to the solution-phase processes [25c]. Each of the microreactors was then subjected to the tandem RCM resin-cleavage conditions employing initiator 3. The products from each microreactor were obtained as a mixture of four compounds (89-92). The library of analogs prepared by this technique was then screened for biological activity [25c]. 

In a related study, Lusinchi [11] reported the synthesis of a new soluble polymer containing a p-alkoxybenzyl alcohol linker, analogous to Wang resin. The polymer was utilized in intermolecular radical addition reactions. The polymer was synthesized by subjecting xanthate 65, formed in three steps from alcohol 63, to styrene polymerization in the presence of lauroyl peroxide... 

Grafting on polypropylene clearly showed the effect of increasing the number of grafting sites and decreasing the substrate polymer melt viscosities. Grafting equimolar styrene-co-MA in solution on polypropylene, by free-radical initiators, has also been disclosed in the patent literature. Carboxy-lation of atactic polypropylene requires a temperature of 150°C. In contrast, effective carboxylation of isotactic polypropylene requires a temperature of at least 170°C. Analogous to PVC, polypropylene grafting reactions were not subject to conventional inhibitors and normal additives in the commercial polymer failed to interfere with the reaction. 

The polymerization of diacrylate monomers functionalized with Schiff base complexes of Cu(IT), Pd(n), and Zn(ll) has been investigated. Thermal polymerizations of monomer 17 (M=Pd and Zn) were successful however, polymers were not obtained when flie copper analog was subjected to tiie same conditions. Photopolymerization of these monomers in the presence of a titanium initiator and their copolymerization with monoacrylate organic monomers were also examined. In aU cases, the copper complexes inhibited the polymerization reaction. The palladium-containing polymers exhibited liquid crystalline properties. ... 

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