Stereoregular polyamides

Munoz-Guerra also studied stereoregular polyamides fully based on d- and L-tartaric acid [73]. The bispentachlorophenyl esters of both 2,3-di-(9-methyl-tartaric acids (22 and 23) were condensed with (2S, 3S )-2,3-dimethoxy-l,4-butanediamine (41) to obtain optically active (PTA-LL) and racemic (PTA-LD) polytartaramides. Fiber-oriented and powder X-ray studies of these polyamides demonstrated that PTA-LL crystallized in an orthorhombic lattice, whereas PTA-LD seemed to adopt a tricUnic structure. In both cases, the polymeric chain appears to be in a folded conformation more contracted than in the common y form of conventional nylons. 

Two stereoregular polyamides based entirely on tartaric acid have been synthesized.95 Tartaric acid derivatives having the d- and L-conllguration were polymerized with (2S, 3S )-2,3-dimethoxy-l,4-butanediamine (113), affording respectively the polyamides 123 and 124. Each diastereoisomeric polymer posses two pairs of stereocenters In the repeating unit, one In the diamine and the other In the diacid counterpart (Scheme 34). 

Varela et al. described some stereoregular hydroxylated polymannaramides [94] by the reaction of o-mannaro-1,4 6,3-dilactone with even-numbered alkylenediamines (n = 2, 6, 8, 10, 12). Hydroxylated stereoregular and non-stereoregular polyamides were also prepared by the same authors [95] from hexamethylene diamine and pentachlorophenyl (2S)-5-oxo-2-tetrahydrofurancarboxylate, synthesized [96] from the chiral (25)-2-hydroxypentane-dioic acid 5,2-lactone. The latter was obtained [97] by deamination of the easily available L-glutamic acid. 

Bou J.J., Mbarren I., Munoz-Guerra S., Synthesis and properties of stereoregular polyamides derived from L-taitaric acid Poly[(2S,3S)-2,3-dimethoxybutylene alkanamide]s. Macromolecules, 27, 1994, 5263-5270. 

Rodriguez-Galdn A., Bou J.J., Munoz-Guerra S., Stereoregular polyamides derived from methylene-L-taitaric acid and aliphatic diamines, J. Polym. Sci. Part A Polym. Chem., 30, 1992, 713-721. 

Zamora R, Bueno M., Molina 1., Orgueira H.A., Varela O., Galbis J.A., Synthesis of carbohydrate-based monomers that are precursors for the preparation of stereoregular polyamides, Tetrahedron Asymm., 7,1996, 1811-1818. 

Optically active stereoregular polyamides with restricted rotation around the amide bond derived from polycondensation of trans cyclic dicarboxylic acids (XXa-e) and of various diamines piperidine (PID), piperazine (PIP), trans-2,5-dimethylpiperazine(DMPIP), 7V,A -dimethylethylene diamine (DMED) and more recently 2,6-diazaspiro-3,3-heptane (DSH) [50]. 

CONFORMATIONAL PROPERTIES OF STEREOREGULAR POLYAMIDES WITH VARYING DEGREES OF STRUCTURAL RIGIDITY... 

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