Asymmetric total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J using acetate migration and RCM reaction

A concise, unified and stereoselective total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J from a common polyhydroxylated cyclohexenol intermediate which was synthesized from readily available D-ribose has been described. The synthetic avenue includes stereoselective Grignard reaction, silyl ether deprotection followed by acetate migration, RCM reaction, oxidative diol cleavage, hydroxymethylation and oxidative rearrangement as key steps.     

树脂吸附法D-核糖发酵液脱色的研究

首次考察了六种不同树脂对D－核糖发酵液的脱色作用,详细地研究了吸附工艺条件对树脂脱色能力的影响．试验结果表明,在25℃下,以1.0BV／h的流速进行吸附时,NKA－Ⅱ树脂对D－核糖发酵液具有良好的脱色效果,脱色率91％,处理量5.7BV;并对树脂再生的条件进行了较详尽研究。     

葡萄糖发酵液D-核糖含量的高效液相色谱分析

D－核糖在生命科学研究领域十分重要,在医药、食品、饲料等工业部门广泛应用,近年来,D－核糖可通过D－葡萄糖在莽草酸营养缺陷型突变株菌种^[1]存在下,经发酵制得,目前国内葡萄糖发酵液中该糖含量分析仍采用苔黑酚光度法,此法没有对发酵液中种种上糖类化合物预先分离,选择性差,得到的是各种糖经合物总含量分析结果,糖类化合物测定的高效液相色谱法有衍生法[2] ,但比较繁琐,近年RI检测器应用于糖类分析日益增多[3,4],但用于葡萄糖发酵液中D－核糖分析尚未见报道,本文采用高效液相色谱法分析葡萄糖发酵液D－核糖含量,并获得良好结果。     

N-(3,4-二甲苯胺基)-D-核糖苷加氢新型负载化镍催化剂

将活性组分镍分别担载于活性炭、海泡石、γ-氧化铝、硅胶、锆胶、钛胶、NaY型分子筛、硅藻土和白土等载体上,用作N-(3,4-二甲苯胺基)-D-核糖苷加氢反应的催化剂.结果表明,载体酸碱性对加氢催化剂的活性与选择性有显著的影响,其中弱碱性的Ni/C是该氢化反应有效的催化剂,N-(D)-脱氧核糖醇基-3,4-二甲苯胺的收率可达35%.     

离子交换法提取D-核糖的研究

采用离子交换法提取D-葡萄糖发酵液中的D-核糖，其中Ca^2 型阳离子交换树脂具有良好的选择性，最佳吸附条件为25℃，以0．5BV／h的流速进行吸附，最佳解吸条件为80℃下，以0．5BV／h的流速进行解吸．解吸液浓缩后加入四倍量乙醇，可得到结晶D-核糖．     

Combined effect of promoter and surfactant on the chromium(VI) oxidation of D-ribose in aqueous media at room temperature

Effect of polypyridine derivatives on chromium(VI) oxidation of D-ribose in aqueous media was studied spectrophotometrically. The oxidized product D-erythrose was detected by paper chromatography. The promoters 1,10-phenanthroline, 2,2?-bipyridine, 2-picolinic acid, and 2,3-dipicolinic acid accelerated the oxidation, whereas isomeric 4,7-phenanthroline, 4,4?-bipyridine, 4-picolinic acid, and 2,6-dipicolinic acid did not influence the oxidation. Formation of Cr(VI)-promoter complex was identified through fluorescence spectroscopy. Rate constants depended on promoter concentration. SDS and TX-100 enhanced the D-ribose oxidation, while CPC retarded the reaction. Location of D-ribose inside micelles was observed through ¹H NMR. DLS study showed that the relative size of SDS and TX-100 micelles expanded in presence of chromium(VI).     

STUDY ON THE DECOLORIZATION OF D-RIBOSE ZYMOTIC FLUID BY RESIN ADSORPTION

1INTRODUCTIONWriboseisimPObotfortheactivitiesoflivingorganismsandcanbewidelyusedinpharmaceutical,foodandforageindustriesll.ZI.Itcanbeproducedbyfermentationofglucosewiththesubnutritionalmutantstrainoftheilliciumoill3.41.ruribosedemoticfluidhasacidicproperty,itScolorisdarkreddish.Itcontainsphosphateion,chlorideionandalittlequantityofsulfateionandoxalateion.Potassiumionandalittlequantityofsodion,calciumionandmagnesiumioncanalsobefound.Becauseofplentyofimpuritiesinthefluidandthedarkcoloroft…