Chiral Poly methacrylamides

In 1974 Blaschke and coworkers introduced new polymer-type CSP materials prepared by suspension polymerization of methacrylamides derived from chiral amines and amino acid esters [187-189]. These CSPs were initially produced in the form of self-supporting beads. However, difficulties arising from extreme polymer swelling and poor mechanical strength prompted later the development of si-hca-supported composite materials with more favorable chromatographic performance characteristics [190]. These improved versions of the CSPs have been com- 

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Chiral poly(meth)acrylamides as CSPs. In 1974, Blaschke reported the preparation and application of soft cross-linked poly(meth)acrylamide polymeric beads (11), which were synthesized by suspension polymerization from acryl or methacrylamides with chirality residing in the side chain of the amine component. Mechanically more stable chiral sorbents have subsequently been produced by polymerizing and covalently anchoring the monomers onto the surface of silica gels [ 192). The CSP obtained by this procedure from A -acryloyl-(S)-phenylalanine ethyl ester as monomer is commercialized by Merck under the tradename ChiraSpher. 

It was subsequently demonstrated that under microwave conditions it was possible to obtain chiral (R)-N-(l-phenylethyl) methacrylamide directly from methacrylic acid and (R)-l-phenylethylamine under solvent-free conditions. Addition of free-radical initiator (AIBN) again led, in a single-step reaction, to optically active poly-... 

The monomers with relatively small N-substituents such as N-methyl methacrylamide afford polymers rich in syndiotacti-city. The bulkier N-isopropyl, N-t-butyl, and N-phenyl derivatives result in polymers with a slightly reduced syndio-tacticity. However, radical polymerization of bulky N-[di (4-butylphenyl)phenylmethyl] methacrylamide (DBuTrMAM, 67) and N-triphenylmethylmethacrylamide (TrMAM, 68) produces a nearly complete isotactic polymer due to helix formation of the polymer chain. When the radical polymerization of these monomers was carried out in the presence of optically active menthol, single-handed helical, optically active polymers were produced. Because poly(TrMAM) was insoluble in solvents, its CD spectra were measured in the solid state to support the chiral structure. 

Morioka K, Suito Y, Isobe Y, Habaue S, Okamoto Y (2003) Synthesis and chiral recognition ability of optically active poly N-[R-a-methoxycarbonylbenzyl]-methacrylamide with various tacticities by radical polymerization using Lewis acids. J Polym Sci A Polym Chem... 

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