Chemical transformations of cyclo and related polymers

The 1:2 regularly alternating copolymer of divinyl ether and maleic anhydride produced via the cyclocopolymerization mechanism has been converted to a number of derivatives, and certain of these derivatives have been found useful as antitumor agents. Citraconic anhydride was substituted for maleic anhydride in the above cyclocopolymerization and its derivatives also exhibited antitumor properties, as did the derivatives of the copolymers of furan with maleic anhydride and with itaconic anhydride, respectively. The divinyl ether‐maleic anhydride copolymer reacts with dimethylformamide to yield a copolymer possessing polyelectrolyte character. The completely methylated copolymer was found to be useful in determining the molecular weight distribution of the original copolymer by gel permeation chromatography. A second series of reactive polymers were prepared by cationic initiation of o‐, m‐, and p‐(2‐vinyloxy)ethoxy‐β‐nitrostyrenes, propagation occurring only through the vinyloxy group. The polymer of the p‐isomer was crosslinked through anionic initiation on the nitrovinyl group. The m‐ and p‐isomers were converted to linear polymers through the nitrovinyl group via anionic initiation which underwent crosslinking through the vinyloxy group upon standing in air. The o‐isomer was not converted to polymer via anionic initiation. This unusual “ortho effect” appears to be a steric effect, as the only ortho derivative of β‐nitrostyrene which has been polymerized by anionic initiation is o‐fluoro‐β‐nitrostyrene. Poly‐m‐β‐dinitrostyrene was converted to the polyanion by sodium methoxide. A third series of reactive polymers were synthesized via anionic initiation on the o‐, m‐, and p‐(2‐vinyloxy)ethoxystyrenes. Propagation occurred through the styrene double bond leaving the vinyloxy group pendant. Hydrolysis of this vinyl ether was accomplished in all cases to yield the poly‐2‐hydroxyethylstyrenes. Further reactions of these polymers with acrylonitrile, phenyl isocyanate, and diisocyanates led to new polymeric systems. Hydrolysis of the vinyloxy group of the original styrenes followed by esterification with acrylyl chlorides led to monomers that were cyclopolymerized by a radical mechanism to polymers containing ten‐membered rings.