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Facile Route for the Synthesis of Adamantane‐Containing Polypeptides through Polycondensation of Activated Urethane Derivative of α‐Amino Acids
Author(s) -
Yamada Shuhei,
Goto Mitsuaki,
Endo Takeshi
Publication year - 2015
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201500069
Subject(s) - condensation polymer , polymer chemistry , chemistry , adamantane , diphenyl carbonate , moiety , copolymer , derivative (finance) , polymer , organic chemistry , transesterification , catalysis , financial economics , economics
A facile route has been discovered for the synthesis of polypeptides containing adamantane moieties in the side chain, poly( N δ‐adamantyl‐ l ‐glutamine) P1 and poly( N γ‐adamantyl‐ l ‐asparagine) P2 , through polycondensation of an N ‐phenoxycarbonyl derivative of the corresponding N δ‐adamantyl‐ l ‐glutamine 1 and N γ‐adamantyl‐ l ‐asparagine 2 , respectively, along with the elimination of phenol and CO 2 . The urethane derivatives are readily synthesized by the N ‐carbamylation of tetrabutylammonium salts of α‐amino acids with diphenyl carbonate. Polycondensation of the urethane derivative proceeds smoothly upon heating to 60 °C in N , N ‐dimethylacetamide using n ‐butylamine ( n ‐BuNH 2 ) as an initiator. Size exclusion chromatography, 1 H NMR spectra, and matrix‐assisted laser desorption/ionization time‐of flight mass spectrometry analyses reveal that polycondensation of 1 with n ‐BuNH 2 yields a well‐defined polypeptide in terms of molecular weight and terminal structure. On the other hand, polycondensation of 2 affords poor molecular weight control and leads to the formation of oligopeptides. Furthermore, using amine‐terminated poly(ethylene‐glycol) in place of n ‐BuNH 2 yields a diblock copolymer composed of polyether and polypeptide segments bearing an adamantane moiety through polycondensation of the urethane derivative.