Synthesis and polymerization of N-carboxyanhydrides of N-benzyl-β-amino acids

✍ Scribed by Albert Zilkha; Yigal Burstein

• Book ID: 102760134
• Publisher: Wiley (John Wiley & Sons)
• Year: 1964
• Tongue: English
• Weight: 801 KB
• Volume: 2
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1964.360020207

✦ Synopsis

The NCAs of the N-benzyl derivatives of 8-alanine, j3-nL-aminobutyric acid, and j3nkaminoisobutyric acid (nonplanar six-membered rings) were prepared by reacting the corresponding N-chloroformyl derivatives, obtained on reaction of the N-benzyl amino acids with phosgene, with triethylamine. Contrary to the others, the NCA of Nbenzyl-palanine polymerized readily on heating in vacuo or in solution, using n-hexylamine or methanolic sodium methoxide as initiators. With n-hexylamine the molecular weights of the polymers obtained in benzene, dioxan, and dimethylsulfoxide, were in accordance with DP = [NCA] /[Initiator], as waa found with conventional five-membered ring NCAs of a-amino acids. With sodium methoxide initiation, FPs of the polymers obtained were smaller than the [NCA]/[Initiator] ratio, contrary to what was found previously with a-amino acid NCAs. The possibility that stereochemical factors are responsible for the differences in polymerization activity of various N-alkyl j 3 as well aa a amino acid NCAs is discussed.