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Syntheses of poly[β‐( l )‐menthyl D ‐ and L ‐aspartates] and their secondary structures
Author(s) -
Yamamoto Hiroyuki,
Hayakawa Tadao
Publication year - 1971
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360100207
Subject(s) - chemistry , chromophore , monomer , random coil , chloroform , polymer , ether , tetrahydrofuran , polymer chemistry , stereochemistry , organic chemistry , circular dichroism , solvent
β‐( l )‐Menthyl D ‐ and L ‐aspartates were prepared by a fusion reaction of N ‐phthalyl D ‐ and L ‐aspartic anhydrides with l ‐menthol, followed by hydrazinolysis. The monomers were then polymerized to poly[β‐( l )‐menthyl D ‐ and L ‐aspartates] by the N ‐carboxyanhydride method. These polymers were soluble in many organic solvents, such as diethyl ether, tetrahydrofuran, chloroform, n ‐bexane, and dioxane. From the results obtained by a study of the optical rotatory dispersions and circular dichroisms, poly [β‐( l )‐menthyl D ‐aspartate] was found to be a β form structure in solution. On the other hand, poly[β‐( l )‐menthyl L ‐aspartate] was a random‐coil structure. These results suggest that the asymmetry of the l ‐menthyl chromophore in the side chain interacts with the polypeptide main chain and causes an extraordinary optical rotation.