𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Polymerization of optical isomers of phenylalanine N-carboxyanhydride by various secondary amines

✍ Scribed by Yutaka Hashimoto; Akimasa Aoyama; Yukio Imanishi; Toshinobu Higashimura

Publisher
Wiley (John Wiley & Sons)
Year
1976
Tongue
English
Weight
705 KB
Volume
15
Category
Article
ISSN
0006-3525

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

In the polymerization of phenylalanine NCA initiated by some secondary amines, the two enatimorphs of phenylalanine NCA were polymerized with the same rate, which was almost twice as high, as that found for the racemic mixture. This stereoselectivity was observed only when the polymerization was initiated by secondary amines which are sterically crowded and reluctant to undergo a nucleophilic addition to NCA. Poly(DL‐phenylalanine) produced in the stereoselective polymerization had a higher molecular weight than that produced in nonstereoselective polymerization. These findings point to the possibility that the stereoselectivity arises only in those polymerizations which are propagated by the activated monomers and not in the propagation involving the terminal amine of the growing polymer. A possible mechanism for the stereoselective polymerization is proposed and examined.

📜 SIMILAR VOLUMES

Polymerization of optical isomers of phe
Polymerization of optical isomers of phenylalanine N-carboxyanhydride by poly (N-methylalanine) diethylamide
✍ Yukio Imanishi; Kazuya Kugimiya; Toshinobu Higashimura 📂 Article 📅 1974 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 400 KB

## Abstract In the polymerization of phenylalanine __N__‐carboxyanhydride (NCA) using poly(__N__‐methyl‐L‐or DL‐alanine) diethylamide as initiator, the polymerization rate was L‐NCA ≃ D‐NCA > DL‐NCA. This is a new type of selective polymerization and indicates the incompleteness of earlier investig

Polymerization of N-carboxyanhydrides of
Polymerization of N-carboxyanhydrides of various α-amino acids using secondary amines as initiator
✍ Yukio Imanishi; Akimasa Aoyama; Yutaka Hashimoto; Toshinobu Higashimura 📂 Article 📅 1977 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 494 KB 👁 1 views

## Abstract In the polymerizations of alanine, γ‐ethyl glutamate, and leucine __N__‐carboxyanhydrides (NCA's) initiated by tertiary amines and some secondary amines such as __N__‐methyl‐L‐alanine dialkylamide, a stereoselectivity was observed: the polymerization rates of L‐ and D‐NCA's were identic

Polymerization of L- and DL-phenylalanin
Polymerization of L- and DL-phenylalanine N-carboxyanhydride by poly(N-methyl-L-alanine)
✍ Yukio Imanishi; Kazuya Kugimiya; Toshinobu Higashimura 📂 Article 📅 1973 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 617 KB

## Abstract Polymerizations of L‐ and DL‐phenylalanine __N__‐carboxyanhydride in nitrobenzene by poly (__N__‐methyl‐L‐alanine) of varying degrees of polymerization (__n__ = 1–30) were investigated. Poly(__N__‐methyl‐L‐alanine) was prepared by the polymerization of __N__‐methyl‐L‐alanine NCA with __

Primary Amine and Solvent-Induced Polyme
Primary Amine and Solvent-Induced Polymerizations of L- or D,L-Phenylalanine N-Carboxyanhydride
✍ Hans R. Kricheldorf; Colin v. Lossow; Gert Schwarz 📂 Article 📅 2005 🏛 John Wiley and Sons 🌐 English ⚖ 168 KB

## Abstract **Summary:** Benzylamine, hexylamine and aniline‐initiated polymerizations of D,L‐phenylalanine and L‐phenylalanine __N__‐carboxyanhydride (D,L‐Phe‐NCA and L‐Phe‐NCA) were performed in various solvents. The isolated polypeptides were characterized by MALDI‐TOF mass spectroscopy. Exclusi

Polymerization of amino acid derivatives
Polymerization of amino acid derivatives by polymer catalysts. V. Polymerization of DL-β-phenylalanine N-carboxyanhydride by several poly(N-alkylamino acid) diethylamides
✍ Masahiko Sisido; Yukio Imanishi; Seizo Okamura 📂 Article 📅 1970 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 410 KB

## Abstract The polymerization of DL‐β‐phenylalanine __N__‐carboxyanhydride (NCA) initiated by poly(__N__‐benzylglycine)diethylamide (DEA) and poly(__N__‐methyl‐DL‐alanine)DEA has been investigated. As previously reported, polysarcosine DEA, poly‐__N__‐ethylglycine DEA, and poly‐__N__‐__n__‐propylg

Polymerization of γ-ethyl-L-glutamate-N-
Polymerization of γ-ethyl-L-glutamate-N-carboxyanhydride initiated by di-n-butyl and di-isopropyl amine
✍ Evaristo Peggion; Alessandro Cosani; Anna Maria Mattucci; Ernesto Scoffone 📂 Article 📅 1964 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 394 KB

The yethyl-bglutamate NCA polymerization initiated by di-n-butyl and di-isopropyl amine was studied. The experimental kinetic curves show an autocatalytic portion with 2530% conversion, followed by a pseudo first-order region which extends up to at least 8590%. In this linear region, the reaction or