Optically Active Polyamides OAPs

Naturally occurring polymers, such as proteins, DNA, and polysaccharides, are optically active. Consequently, the design, characterization, and preparation of chirad pol)oners are of particular interest [89]. The methods of preparing OAPs involve the pol)anerization of optically active monomers and as)anmetric pol)nnerization, which produces OAPs starting from optically inactive monomers. Concerning the aromatic PA synthesis, the simplest approach, starting with chiral monomers, is commonly used. 

The same research group [90] reported the preparation of OA (PAIs) derived from N,N-(4,4 -oxydiphthaloyl)-bis-(s)-(+)-valine diacid chloride. The polymers were prepared by the reaction of aromatic diamines with the diacid by classical low-temperature solution polycondensation (reaction time 2 h at -5°C and 8 h at rt), high-temperature polycondensation (reflux conditions, reaction time Imin), and MW polycondensation reaction (reaction time 6min). Comparable results were obtained for all polycondensation processes. 

The authors further synthesized another series of PAIs derived from trimellitylimido-L-phenylalanine [91]. The direct polycondensation reaction of the monomer imide-diacid with different diamines rendered high yield PAIs with relatively low values between 0.21 and 0.45 dL/g. All the above compounds were fully characterized by IR spectroscopy and elemental analyses, the [a]p varied between -1.0 and -3.6 

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