Halo‐isocyanates as ‘transformation’ reagents

Abstract

The advantages of halo-isocyanates as 'transformation' reagents in the synthesis of block and graft copolymers are elaborated. These compounds permit polymeric blocks of vinyl units to be attached to a wide range of starting materials, natural or synthetic. Two stages are involved-isocyanation and grafting-and both may be carried out homogeneously or heterogeneously. Attention is here focused on poly(ether-urethanes), e.g. Biomer, dextran and poly(ethylene glycol) to which chains of several water-soluble polymers have been attached.

Modification of Biomaterials to Improve Blood Compatibility

“…Two reagents which have proved very effective for such purposes are haloisocyanates (more properly called halo-alkyl isocyanates or halo acylisocyanates), two examples of which are shown in [12] and 2-isocyanatoethyl methacrylate [13].…”

“…Interesting monomers [14], [15], have been prepared from several a-amino acids and also from amino sugars, e.g. glucamine, by reacting these compounds with [13]. Poly(ethylene glycol) (pEG) may also be converted to a polymerizable vinyl monomer [16] by reaction with [13].…”

“…glucamine, by reacting these compounds with [13]. Poly(ethylene glycol) (pEG) may also be converted to a polymerizable vinyl monomer [16] by reaction with [13]. We have coupled this monomer to Biomer by free-radical polymerization, using the halogen-functionalized form of Biomer, as indicated in Scheme 2.…”