Arabinogalactan propargyl ethers: Au-catalysed hydroamination by imidazols. (15th October 2020)

• Record Type: Journal Article
• Authors: Grishchenko, Lyudmila A.; Parshina, Lidiya N.; Larina, Lyudmila I.; Belovezhets, Lyudmila A.; Klimenkov, Igor V.; Ustinov, Alexander Yu.; Trofimov, Boris A.
• Is Part Of: Carbohydrate polymers. Volume 246(2020)
• Publication Date: 2020-10-15
• Subjects: Arabinogalactan functionalization -- Imidazole derivatives -- Hydroamination -- Gold-catalysis -- XPS study -- Antimicrobial activity; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2020.116638
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Gold-catalyzed addition of imidazole molecules to arabinogalactan propargyl ether. The degree of substitution by N-alkenylimidazole moieties reaches 1.6. Reaction accompanies by reduction of Au(III) to Au(I)/Au(0). Hydrochlorides of Au-arabinogalactan derivatives show high antibacterial activity. Abstract: A method for the synthesis of pharmacologically prospective arabinogalactan (AG) imidazole- and benzimidazole derivatives in a yield of up to 97 % via Au(III)-catalyzed hydroamination of AG propargyl ethers has been developed. It is found that in the presence of 5 mol% HAuC14 and 10-fold excess imidazole relative to the propargyl groups, the hydroamination successfully competes with cross-linking processes to afford products soluble in DMSO and aqueous HC1 solutions (degree of substitution of imidazolylpropenyl fragments 0.5–1.8, yield 62–97 %). It is established that under the conditions of hydroamination Au(III) is reduced to give mainly Au(0) and minor amounts of Au(I), which are contained in AG imidazole derivatives as particles of 190−640 nm in size. Hydrochlorides of Au-containing AG imidazole derivatives show high bacteriostatic activity with respect to test gram-positive microorganisms and thus confirming their prospects as new AG-derived bioactive agents.