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Yen-Yuan Chen Ryuichi Oshima Kenichi Hatanaka Toshiyuki Uryu 《Journal of polymer science. Part A, Polymer chemistry》1986,24(7):1539-1550
We report herein studies of grafting of MMA onto (1 → 5)-α-D -ribofuranan and (1 → 5)-α-D -xylofuranan by ceric ion initiation both in water and in dimethyl sulfoxide (DMSO). In aqueous medium, the graft polymer having high grafting (%) can be obtained easily without adding any nitric acid. The degradation of polysaccharide by the acidic ceric ion solution is not serious; 73–82% of its original molecular weight remained after the polymerization. In DMSO, graft polymers having lower grafting (%) and lower molecular weight of grafts were obtained. 相似文献
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HU Yen-Yi RU Wan-Huey WEI Chao-Jen LIN Sheu-Jen LAY Yen-Yuan YEH Shun-Tsai YANGTeng-Kuei 《高等学校化学学报》2000,21(Z1):429
Recently, we found the N-(hydroxyalkyl) aza-rings 1 can produce 2-oxazolidine 2 through electrolysis. With the chiral side chain, the 2-oxazolidine 2 can generate a new chiral center at the 0-aminocarbon when treated with Grignard reagents. Repeat the process of electro-oxidation and substitution by Grignard reagents, we can prepare the two most popular alkaloids bases, pyrroliding and piperidine, with substitutions in an enantioselective fashion. This presentation will discuss the efficiency of electro-oxidation of aza-ring compounds in terms of the oxidation conditions, such as the applied potential, quantity of electricity, solvent effect,and temperature effect. Meanwhile, several demonstrative syntheses of chiral alkaloids, such as Monomorine,(-)-pyrroliding 197B, and(-)-Solenopsin A, will also be presented. 相似文献
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Yen-Yuan Chen Ryuichi Oshima Ju Kumanotani 《Journal of polymer science. Part A, Polymer chemistry》1985,23(5):1283-1292
Pullulan-g-poly(p-acetoxystyrene) ( I ) was prepared using ammonium persulfate (APS) as an initiator in dimethylsulfoxide (DMSO) solution. I was deacetylated by hydrazine hydrate to yield pullulan-g-poly(p-hydroxystyrene) ( II ). The degree of polymerization of the grafted poly(p-hydroxystyrene) chain ( III ) was 15–20. Despite the effective grafting (%), this method caused the degradation of pullulan. The number of branch polymer chains per pullulan molecule were evaluated to be 0.9 to 2.5 from number average molecular weights of the permethylated II and III . The glass transition temperature of II was higher than that of III , indicating that the polar hydroxyl groups of pullulan in the graft polymer caused an increase in the rigidity of the grafted polymer chains. Pullulan-g-poly(o-hydroxystyrene) and pullulan-g-poly(MMA) were also readily prepared by this method. 相似文献
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