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。     

大孔树脂分离纯化藏药白花龙胆花总黄酮的研究

考察了HPD-826、HPD-417、ADS-17、HPD-722、HPD-450、AB-8、HPD-600、D-101,共8种大孔树脂对藏药白花龙胆花总黄酮的吸附和解吸性能,通过静态吸附量和解吸附率及静态吸附曲线的绘制,筛选出AB-8树脂的效果最佳;以AB-8树脂为目标,进行了动态吸附实验,考察了上柱液浓度、pH值、上柱液流速、乙醇浓度、解吸剂流速、解吸体积等对AB-8树脂吸附和解吸效果的影响,确定出AB-8树脂动态吸附白花龙胆花总黄酮的最佳条件:上柱液浓度为6.5mg/mL,pH为3.79,上柱流速4BV/h;最佳洗脱条件:用50%乙醇进行洗脱,解吸流速为3BV/h,解吸体积4BV。在此条件下,白花龙胆花总黄酮纯度由原来的22.10%,变为65.75%,产品精制倍数为65.75%/22.10%=2.97,表明AB-8树脂可用于白花龙胆花总黄酮的分离纯化。     

大孔吸附树脂分离纯化枳实中辛弗林的研究

以辛弗林的吸附量、解吸率和所得粉末中辛弗林的含量为指标,从选用的6种大孔吸附树脂中筛选出较好的AB-8树脂。通过静态和动态实验,对辛弗林在AB-8树脂上吸附和解吸的条件进行优化,并考察其吸附等温线、吸附和解吸性能。结果表明,在环境温度约25℃下,使用AB-8树脂纯化辛弗林的较优工艺参数为:上柱液pH值7～8,流速2BV/h,溶液处理量3BV,洗脱剂为20%乙醇,洗脱速度1BV/h,收集洗脱液3BV。按此工艺条件,辛弗林的解吸率为87.2%,3BV洗脱液浓缩干燥后,所得粉末中辛弗林含量为56.6%。     

NAK-12树脂脱除蚕蛹复合氨基酸异味及褐变物质的研究

本文研究了用NAK－12吸附树脂脱除蚕蛹复合氨基酸异味及褐变色素的条件，初步分析了蚕蛹复合氨基酸异味产生的原因，实验结果表明：当流速为3BV／h时，1ml NAK-12吸附树脂能吸附1．75g蚕蛹复合氨基酸中的异味物质；能吸附1．45g蚕蛹复合氨基酸中的褐变物质。甲醇是异味物质和褐变物质的良好洗脱剂，用pH1．0的甲醇以1BV／h流速洗脱，仅用3．5BV的洗脱剂即可完全洗脱异味物质和褐变物质，蚕蛹复合氨基酸异味产生的可能机理是：加热蚕蛹复合氨基酸液时，其苯丙氨酸，蛋氨酸，蛋氨酸，异亮氨酸，亮氨酸，苏氨酸被氧化脱氨，生成挥发性醛，而其褐变则是赖氨酸，精氨酸与还原糖发生Maillard反应生成褐变物质引起的。     

大孔吸附树脂提取青蒿素的研究

探讨了大孔吸附树脂提取青蒿素的方法。以青蒿素的吸附量,青蒿素含量,青蒿素收率和提取率为考察指标,确定大孔吸附树脂提取青蒿素的工艺条件。研究结果表明,ADS-17树脂对青蒿素的吸附量大,解吸容易,可用于提取黄花蒿中青蒿素的工业化生产,其工艺条件为:青蒿素最大吸附量为112.30mg/g,吸附流速为2BV/h,洗脱剂为90%乙醇,解吸流速为2BV/h,青蒿素含量大于99%,收率高达0.3%,提取率高达75%以上。     

大孔吸附树脂分离纯化金银花中黄酮类物质的研究

比较了AB-8、S-8、NKA-9和D-101 4种大孔吸附树脂对金银花提取液中黄酮类物质的吸附及解吸附性能.在静态吸附试验基础上,筛选出效果较好的D-101树脂进行动态试验研究,结果表明,D-101树脂在30℃下对金银花黄酮类物质的静态吸附-动态解吸较优的工艺参数为:上样液pH值2.46,解吸液为95%乙醇,解吸液的流速为3mL/min,pH值11,4.5BV解吸液即可完全洗脱被树脂吸附的黄酮类物质,其解吸率高达98.00%.在试验研究范围内,树脂吸附金银花黄酮是自发性放热过程,并且符合Langmuir方程,此外树脂对黄酮的吸附动力学可用Pseudo-second-order模型较好地拟合,其表观吸附速率常数为Kso℃=3.43×10-2g/(mg·min).     

XAD-16树脂分离纯化怀菊花黄酮的工艺研究

研究XAD-16树脂分离纯化怀菊花黄酮的工艺,探讨了吸附过程中树脂的等温吸附与吸附动力学,并应用Langmuir方程与Freundlich方程对吸附过程进行了拟合。确定了XAD-16树脂分离怀菊花黄酮的最佳工艺条件:上样浓度2.0mg/mL,上样流速1BV/h,冲洗杂质用水量11BV,洗脱剂为85%(体积分数)乙醇,洗脱流速2BV/h,洗脱剂体积5BV。此时总黄酮的解吸率为83.9%。在此条件下,经过XAD-16树脂分离纯化后,怀菊花总黄酮含量达到77.2%。     

大孔弱酸树脂对妥布霉素纯化的工艺研究

工业生产中妥布霉素发酵液粗提物的纯度只能达到50~60%,通常采用强酸树脂进行纯化,但纯化纯度很难达到国家药典要求。本文比较了5种阳离子交换树脂对妥布霉素的吸附性能,利用静态吸附与动态吸附实验优选出了大孔弱酸树脂HZ-3B,并对其纯化妥布霉素工艺进行了进一步的优化:选用浓度为5mg/m L,pH值为6.8~7.2的妥布霉素溶液以9BV/h的流速进行上样,上样200BV;然后利用0.125mol/L的氨水溶液作为解吸液,以6BV/h的流速进行解吸,合并解吸液。HPLC分析结果显示,妥布霉素纯度由50~60%提升到了97.15%,收率为89.52%,且无其他氨基糖苷类抗生素杂质,达到了国家药典的要求。     

大孔吸附树脂分离提取多杀菌素

采用大孔吸附树脂法分离提取多杀菌素.从11种大孔吸附树脂中筛选出DM11进行了静态、动态吸附性能实验,并考察了不同吸附、解吸条件的影响.结果表明,DM11的静态吸附容量为25.63mg/g(wet resin),其吸附等温线符合Langmuir吸附等温式.采用丙酮做洗脱剂,洗脱率为97.5%,动态吸附最佳吸附pH为9.5,吸附流速为6BV/h,穿透吸附容量为21.2mg/ml(wet resin),洗脱流速1.5BV/h.     

大网格吸附剂提取头孢氨苄

本文研究了用大网格吸附剂提取头孢氨苄的方法，包括吸附剂和解吸剂的筛选，吸附条件和解吸条件的考察。确定了用H—103型树脂在pH5、流速1／10（V／V／min）条件下吸附；用50％丙酮在pH1．5、流速1／30（V／V／min）条件下解吸。吸附容量可达75mg／ml，是国内报道过的CAD—40的3倍，是国外报道过的DiaionHP－20的3．8倍，解吸率可达92％以上。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.