Direct Amidation of Poly(γ-glutamic acid) with Benzylamine In Dimethyl Sulfoxide

• Published in: Biomacromolecules Vol. 8; no. 5; pp. 1624 - 1632
• Main Authors: Novak, Levente, Banyai, Istvan, Fleischer-Radu, Judit Eva, Borbely, Janos
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.05.2007; Amer Chemical Soc
• Subjects: Amides - chemistry; Aminoacid polymers; Applied sciences; Benzylamines - chemistry; Biochemistry & Molecular Biology; Chemistry; Chemistry, Organic; Dimethyl Sulfoxide - chemistry; Exact sciences and technology; Life Sciences & Biomedicine; Physical Sciences; Physicochemistry of polymers; Polyglutamic Acid - chemical synthesis; Polyglutamic Acid - chemistry; Polymer Science; Science & Technology; Synthetic biopolymers; SOLID-STATE POLYMERIZATION; AMINES; DIMETHYLSULFOXIDE; CONDENSATION; RAPID SYNTHESIS; POLYCONDENSATION; SALTS; POLYAMIDES; SOLVENT; CARBOXYLIC-ACIDS; Glutamic acid copolymer; Homogeneous reaction; Chemical modification; Reaction order; Preparation; Aminoacid copolymer; Glutamic acid polymer; Gamma benzyl glutamate copolymer; Experimental study; Primary amine; Amidation; Growth from solution
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm0612182

Partially benzylamidated, amphipathic poly(γ-glutamic acid) (BzPGA) was synthesized from poly(γ-glutamic acid) (PGA) and benzylamine by direct amidation in dimethyl sulfoxide (DMSO). Benzylamine and PGA were heated in DMSO for 1 to 26 h at temperatures between 110 and 130 °C, producing derivatives of various degrees of benzylamidation as a function of the reaction time and temperature. Neither any carboxyl-activating agent nor catalyst is needed for the reaction to proceed. After purification by dialysis, the product was identified by 1H and 13C 1D and 2D NMR in DMSO-d 6. BzPGA prepared by the new direct amidation method was identical to that obtained with a conventional carbodiimide-mediated reaction in water. The one-pot amidation procedure described in the present article can probably be applied to the synthesis of amides from other amines and carboxylic acids.