Syntheses and conformational studies of poly‐β,N‐alkyl L‐asparagines

  title={Syntheses and conformational studies of poly‐$\beta$,N‐alkyl L‐asparagines},
  author={Tadao Hayakawa and H Yamamoto and Naomi Aoto},
Several β,N‐alkyl L‐asparagines were prepared from the phthalyl and benzyloxycarbonyl derivatives. High‐molecular‐weight poly‐β,N‐benzyl L‐asparagine and poly‐β,N‐(1)‐phenethyl L‐asparagine were prepared from the corresponding N‐carboxyanhy‐drides. From the results obtained by a study of the infrared absorption spectra and the optical rotatory dispersion, poly‐β‐N‐benzyl L‐asparagine was found to be a random coil structure in dichloroacetic acid and the optical rotatory dispersion curves… Expand
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Synthesis and conformational study of poly(Nϵ‐benzyl‐L‐lysine) and its benzyloxycarbonyl derivative
The solvent‐and pH‐induced conformational changes are examined in order to investigate the influence of benzyl group and the breakdown of the helical conformation is found to occur at 8% dichloroacetic acid in chloroform‐dichloroACetic acid mixture. Expand
Syntheses and Conformational Studies of Polyacidic Amino Acids Containing Optical Active Side Chains
The syntheses and physicochemical properties of poly ( β-alkyl aspartate) and poly( γ-alkyl glutamate) have been widely investigated (1–11). Optical rotatory dispersion (ORD) and circular dichroismExpand


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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 toExpand
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γ‐(l)‐Menthyl L‐ and D‐glutamates were prepared by a fusion reaction of N‐phthalyl‐L‐ and D‐glutamic anhydrides with l‐menthol, followed by hydrazinolysis. The monomers were polymerized toExpand
Conformational studies of polymers and copolymers of L‐aspartate esters. I. Preparation and solution studies
An alcoholysis method is described for the modification of high molecular weight poly(β‐benzyl L‐asparatate); by this method the benzyl groups in the polypeptide have been replaced by methyl, ethyl,Expand
Conformational studies of polymers and copolymers of L‐aspartate esters. II. Infrared studies and the factors involved in the formation of the ω‐helix
The frequency ranges for the two helix senses are given and have been used to show that poly (β‐n‐propyl L‐aspartate) in chloroform solution undergoes a transition from the right‐handed to the left‐handed helix form on heating. Expand
Synthesis of poly‐L‐asparagine and poly‐L‐glutamine
Poly‐β‐N‐diphenylmethyl‐L‐asparagine and poly‐γ‐N‐diphenylmethyl‐L‐glutamine were prepared from the corresponding N‐carboxyanhydrides. Poly‐L‐aspuragine and poly‐L‐glutamine were obtained by removalExpand
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β-p-Methyl, chloro, cyano and nitrobenzyl-L-aspartates were synthesized, and the respective homopolymers and copolymers of these β-(p-substituted benzyl)-L-aspartates with β-benzyl-L-aspartate wereExpand
Circular dichroism measurements of benzyl L‐aspartate–nitrobenzyl L‐aspartate copolymers and their use in detecting and characterizing preferred polymer conformations
We have examined the nature of the circular dichroism band at 330 mμ for a series of copolymers of β‐p‐nitrobenzyl L‐aspartate with β‐benzyl L‐aspartate. The circular dichroism band arises from anExpand
Conformational aspects of polypeptides. XXV. Solvent and temperature effects on the conformations of copolymers of benzyl and methyl L‐aspartate with nitrobenzyl L‐aspartate
For the first time, the circular dichroism spectra in which the n‐π* peptide band of a left‐handed helical conformation is almost completely evident are reported. Expand
Conformational aspects of polypeptides. XI. The nitroaromatic effect
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The observation of the circular dichroism (240–290 mμ) due to the aromatic side chain indicates that, in a chloroform solution, even the side-chain aromatic rings of the copolyaspartate chain in theExpand