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1.
采用无有机模板剂一步法制备了Ru/ZSM-5催化剂,利用X射线衍射、N_2吸附-脱附、NH_3-程序升温脱附和CO_2-程序升温脱附、扫描电镜和透射电镜等方法对催化剂进行了表征.考察了反应温度、钌负载量和催化剂重复利用等因素对Ru/ZSM-5上葡萄糖加氢反应性能的影响,并与浸渍法制备的Ru/ZSM-5催化剂进行了对比.结果表明,与传统浸渍法相比,一步法制备的Ru/ZSM-5催化剂钌粒子具有更高的分散性和稳定性.在120℃和4 MPa的温和反应条件下,葡萄糖接近完全转化,山梨醇选择性高达99.2%,催化剂可重复利用5次,仍保持较高活性.  相似文献   

2.
任清  张阳 《分析试验室》2004,23(6):19-21
建立了大鼠坐骨神经中糖醇化合物葡萄糖、山梨醇、肌醇同时测定的毛细管气相色谱分析方法。选择甘露糖为内标,先加入盐酸羟胺吡啶溶液进行肟化反应,再加入乙酸酐溶液进行乙酰化反应,将葡萄糖、山梨醇、肌醇转化成糖腈乙酰酯化合物,经SE 30毛细管柱色谱分离,氢火焰离子化检测器检测。葡萄糖、山梨醇、肌醇的回收率均在93%以上,其检出限分别为0.40、0 30、0.26ng/μL。对比测定了正常对照组、糖尿病组、某中药复方治疗组大鼠坐骨神经中以上3种糖醇含量。  相似文献   

3.
采用无有机模板剂一步法制备了Ru/ZSM-5催化剂,利用X射线衍射、N2吸附-脱附、NH3-程序升温脱附和CO2-程序升温脱附、扫描电镜和透射电镜等方法对催化剂进行了表征.考察了反应温度、钌负载量和催化剂重复利用等因素对Ru/ZSM-5上葡萄糖加氢反应性能的影响,并与浸渍法制备的Ru/ZSM-5催化剂进行了对比.结果表明,与传统浸渍法相比,一步法制备的Ru/ZSM-5催化剂钌粒子具有更高的分散性和稳定性.在120℃和4 MPa的温和反应条件下,葡萄糖接近完全转化,山梨醇选择性高达99.2%,催化剂可重复利用5次,仍保持较高活性.  相似文献   

4.
利用硼酸与茜素红S和糖中的邻二羟基可逆结合的特点,以硼酸为中介运用竞争结合作用机理构建单糖分析法.在pH7.4的KH2PO4-NaOH缓冲溶液中,茜素红S作为指示剂与硼酸结合生成ARS-BA配合物,其结合常数为5.09×102L/mol.糖与指示剂ARS竞争结合硼酸使指示剂游离出来,产生明显的颜色变化,据此建立糖的识别方法.考察了D-葡萄糖、D-山梨醇、D-半乳糖、D-甘露糖、D-果糖、D-阿拉伯糖和L-阿拉伯糖对上述ARS-BA体系光谱的影响.结果显示:该体系对D-山梨醇和D-果糖有较好的光谱响应,其光谱变化灵敏度依D-山梨醇>D-果糖>D-阿拉伯糖~D-半乳糖>D-葡萄糖>D-甘露糖>L-阿拉伯糖之序.  相似文献   

5.
建立离子色谱法测定乳糖玉米淀粉共处理物中的有关物质.采用离子色谱法(安培检测器)进行测定,色谱柱为CarPac PA20分析柱,流动相为水–氢氧化钠溶液(0.25 mol/L)–乙酸钠溶液(0.25 mol/L),梯度洗脱,流量为0.4 mL/min,柱温为30℃.蔗糖、葡萄糖、半乳糖、乳糖的质量浓度在0.05~2μg...  相似文献   

6.
几种齐墩果酸糖缀合物的合成   总被引:6,自引:2,他引:6  
曲峰  李英霞  张一纯  臧静 《有机化学》2003,23(3):249-257
报道了齐墩果酸与四种单糖和二糖(葡萄糖、半乳糖、乳糖及葡萄糖醛酸)进 行糖苷化制备糖缀合物的方法。在合成过程中首先将葡萄糖、半乳糖及乳糖转化成 相应的全苯甲酰三氯亚胺酯糖基供体(10a-10c),将葡萄糖醛酸转化成为1-溴代 乙酰葡萄糖醛酸甲酯糖基供体(10d);在齐墩果酸的28-位羧基上进行酰胺化引入 ω-氨基羧酸甲酯得到其衍生物6。然后10a-10c在TMSOTf的催化下与化合物6的3-位 羟基进行β-糖苷化;10d在AgOTf的催化下与6进行β-糖苷化,最后脱掉保护基得 到相应的糖缀合物13a-13d,所有目的化合物均为新化合物,其结构经IR,^1H NMR,^13C NMR,2D-COSY,HMQC,DEPT及HRMS进行了确证。  相似文献   

7.
为了研究正电子核素18F标记的葡萄糖转运蛋白显像剂6-18氟-6-脱氧葡萄糖的制备及在小鼠体内的生物学分布, 以D-葡萄糖为起始原料, 经过丙酮和苯甲醛对1,2,3,5位羟基的定位保护, 然后用对甲苯磺酰氯和6位的羟基反应得到能被18F-进攻的离去基团, 最后用18F-离子通过亲核取代反应实现对葡萄糖6位的氟代标记; 反应中间体用NMR和MS表征, 最终产物用标准品6-19FDG在HPLC下对照确认, 测定放化纯度, 观察其在小鼠体内的生物学分布. 6-18氟-6-脱氧葡萄糖的放射性标记过程需35 min(从加速器轰击结束算起), 放化产率70%±5%(校正后, n=5), 放化纯度>95%. 小鼠体内的生物学分布表明, 各个器官在1.0 min达到峰值, 然后逐渐平衡. 初步研究结果表明, 6-18FDG是一种很有价值的葡萄糖转运蛋白显像剂, 为以后的体内外研究及活体显像奠定了基础.  相似文献   

8.
采用1-苯基-甲基-吡唑啉酮(PMP)柱前衍生化-反相高效液相色谱(HPLC)法建立了8种常见单糖的分离模式,并用于木糖结晶母液单糖组成的定量分析.结果表明:木糖结晶母液至少由甘露糖、鼠李糖、纤维二糖、葡萄糖、半乳糖、木糖、阿拉伯糖及岩藻糖8种单糖组成,其中以葡萄糖、半乳糖、木糖和阿拉伯糖为主.以峰高定量,8种单糖的浓...  相似文献   

9.
刘侠 《分析科学学报》2008,24(4):485-487
对食用仙人掌中葡萄糖的测定方法进行了研究,采用单因素和正交实验法测定食用仙人掌中葡萄糖含量,其最佳条件为:水解时加入盐酸20 mL,反应滴定温度60℃,反应液pH 5.0,水解时间30 min.该方法简便、可行.  相似文献   

10.
为拓展脱氧葡萄糖(DG)在肿瘤代谢显像中的应用,以新型核素64Cu标记葡萄糖胺-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA-DG).通过优化反应条件,于25℃反应30 min后得到高放化纯度和高比活度的标记化合物64Cu-DOTA-DG,标记产物经放射性高效液相色谱(Radio-HPLC)检测.体外稳定性实验结果表明,64Cu-DOTA-DG有良好的稳定性.将64Cu-DOTA-DG通过尾静脉注射入荷瘤肝癌细胞(Hep-G2)裸鼠体内,分别于注射后1和3 h进行小动物正电子发射断层扫描(Micro-PET)显像.结果表明,其在肿瘤部位有所富集.64Cu-DOTA-DG的合成及分子显像研究拓宽了以18F-氟代脱氧葡萄糖为代表的肿瘤代谢类显像剂的应用范围,为新型核素标记肿瘤代谢显像剂提供一种新途径.  相似文献   

11.
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%.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
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.  相似文献   

20.
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.  相似文献   

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