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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。 相似文献
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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%。 相似文献
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NAK-12树脂脱除蚕蛹复合氨基酸异味及褐变物质的研究 总被引:6,自引:0,他引:6
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。 相似文献
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大孔吸附树脂分离纯化金银花中黄酮类物质的研究 总被引:3,自引:0,他引:3
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). 相似文献
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《离子交换与吸附》2015,(6)
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。 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献
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Xi-Liu YunWen-Ying Bi Jian-Hui HuangYu Liu Daisy Zhang-NegrerieYun-Fei Du Kang Zhao 《Tetrahedron letters》2012,53(38):5076-5080
A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring. 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献