Lineare und sternförmige hybrid‐polymere, 4 Ein neuer weg zur synthese von cellulose und amylose enthaltenden blockcopolymeren

• Published in: Die Makromolekulare Chemie 1988-09, Vol.189 (9), p.1965-1985
• Main Authors: Pfannemüller, Beate, Dengler, Thomas
• Format: Article
• Language: English
• ISSN: 0025-116X; 0025-116X
• DOI: 10.1002/macp.1988.021890901

(A‐B)n‐Block copolymers containing oligosaccharide blocks (A) and synthetic polymer blocks (B) coupled by amide linkages were synthesized. As starting material fully substituted cellulose and amylose derivatives with protecting groups of variable stability were used: triacetates, tricarbanilates and trimethyl ethers. The reaction steps were as follows: (i) trisubstituted oligosaccharides in the range of 2 < P̄n < 20 with OH endgroups at C‐1 and C‐4 were obtained by acidolysis or alcoholysis of the polysaccharide derivatives. (ii) By reaction of the OH endgroups with isocyanatoacetic ethyl or methyl ester, ester endgroups were introduced. (iii) Condensation with diamines [dodecamethylenediamine, NH2‐terminated poly(oxyethylene)] could be achieved by direct amidation of the ester endgroups in the case of the tricarbanilates and trimethyl ethers. As an alternative route, saponification of the ester endgroups and conversion into the more reactive p‐nitrophenyl ester was investigated. While condensation of the p‐nitrophenyl ester with diamines proceeds under mild conditions, difficulties arise in the quantitative p‐nitrophenylation of the COOH groups. In the case of the triacetates acetyl and ester endgroups were cleaved simultaneously by saponification, leading to unsubstituted oligosaccharides with COOH or lactone groups at both ends, a building block suitable for various reactions.