title: Preparation and structural characterization of poly-mannose synthesized by phosphoric acid catalyzation under microwave irradiation.
abstract: Poly-mannose with molecular weight of 2.457 kDa was synthesized using d-mannose as substrate and phosphoric acid as catalyst under the condition of microwave irradiation for the first time. The optimum reaction conditions were microwave output power of 900 W, temperature 115°C, proton concentration 2.5 mol/L, and microwave irradiation time 5 min. The actual maximum yield was 91.46%. After purified by Sepherdex G-25 column chromatography, the structural features of poly-mannose were investigated by high-performance anion-exchange chromatography (HPAEC), high-performance gel-permeation chromatography (HPGPC), infrared (IR) spectroscopy, methylation analysis and NMR spectroscopy analysis ((1)H, (13)C, COSY, TOCSY, HMQC, and HMBC). HPAEC analysis showed that the composition of synthetic polysaccharides was d-mannose, its purity was demonstrated by HPGPC as a single symmetrical sharp peak, and additionally IR spectra demonstrated the polymerization of d-mannose. Methylation analysis and NMR spectroscopy revealed that the backbone of poly-mannose consisting of (1→3)-linked β-d-Manp, (1→3)-linked α-d-Manp, and (1→6)-linked α-d-Manp residues, and the main chain were branched at the O-2, O-3, O-4, O-6 position.
authors: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu, PR China; State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, PR China.
authors: Haisong
authors: H
authors: Wang
authors: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu, PR China; State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, PR China.
authors: Xiangrong
authors: X
authors: Cheng
authors: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, PR China.
authors: Yonghui
authors: Y
authors: Shi
authors: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu, PR China; State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, PR China. Electronic address: lgw@jiangnan.edu.cn.
authors: Guowei
authors: G
authors: Le
mesh_terms: D002384:Catalysis; D008351:Mannans / Q000138:chemical synthesis* / Q000737:chemistry; D008872:Microwaves; D010756:Phosphoric Acids / Q000737:chemistry; D058105:Polymerization
chemical_list: D008351:Mannans; D010756:Phosphoric Acids; C097323:polymannose; C030242:phosphoric acid
keywords: Ethanol (PubChem CID: 702); Methylation analysis; Microwave irradiation; NMR; Phosphoric acid (PubChem CID: 1004); Poly-mannose; Trifluoroacetic acid (PubChem CID: 6422); d-mannose (PubChem CID: 18950)