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以(R)-pantolactone为原料,经还原、羟基保护、环合、开环、脱保护、氧化等8步反应,合成了(3S)-2,2-二甲基-3-苄氧基癸酸,总收率为40.0%. 相似文献
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以1,3-二氟苯为起始原料,依次经傅-克酰基化,1H-三氮唑取代,环氧化,胺解,4H-三氮唑环化,磷酸酯化和钯碳加氢反应等7步反应合成了福司氟康唑的主要杂质--2-(2,4-二氟苯基-1-(1H-1,2,4-三氮唑-1-基)-3-(4H-1,2,4-三氮唑-4-基)-2-丙基磷酸二氢酯,纯度98%,总收率7.8%,其结构经1H NMR确证。 相似文献
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高光学纯度的(S)-4-三甲基硅基-3-丁炔-2-醇是一种重要的药物手性中间体. 以4-三甲基硅基-3-丁炔-2-酮作为模型底物, 从51株不产氧光合细菌中筛选出一株高效目标功能菌株Thiocapsa roseopersicina SJH001作为生物催化剂进行光动不对称加氢催化反应, 在未经优化的反应条件下, 其产物(S)-TMSBL的ee值高于99%, 产率高达80%以上. 从Thiocapsa roseopersicina SJH001分离得到了新的NADPH依赖型氧化还原酶[(S)-氧化还原酶和(R)-氧化还原酶]. 粗酶经硫酸铵分级沉淀、Q-sepharose阴离子交换层析、Sephacryl S-200丙烯葡聚糖凝胶过滤层析后在SDS-PAGE上显示为单一条带, 其酶蛋白的相对分子质量为44.5 kDa, 相对酶活为449.8 U/mg, 高于文献报道的同类具有对映体选择性氧化还原酶. 通过比较光照强度、pH值、反应前对菌体细胞热预处理、底物浓度对Thiocapsa roseopersicina SJH001胞内氧化还原酶的活性和构型产生的影响, 进一步在分子水平阐明了光动不对称加氢催化反应的机理. 相似文献
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2,6-二氨基-3,5-二硝基吡啶-1-氧化物的合成新方法 总被引:5,自引:0,他引:5
研究了2,6-二氨基-3,5-二硝基吡啶-1-氧化物(ANPyO)的合成新方法. 以2,6-二氨基吡啶为起始原料, 经酰基化、N-氧化、硝化三步反应得到ANPyO, 总收率为75%. 测试了ANPyO的爆速、爆压、DSC, 以及电火花感度和落锤感度, 同1,3,5-三氨基-2,4,6-三硝基苯(TATB)的性能进行了对比, 结果表明ANPyO综合性能和TATB基本相当. 用1H NMR, MS和红外光谱对ANPyO及其中间体结构进行了表征. 相似文献
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2, 5-呋喃二甲酸二甲酯(DMFDCA)这一生物质衍生的增值化学品是石油基聚合物单体对苯二甲酸(TPA)的理想替代品。本研究采用一步共热解法合成了两种廉价金属修饰的氮掺杂多孔碳催化剂CoMn@NC,并将其用于5-羟甲基糠醛(HMF)在温和条件下的需氧氧化。由Co3Mn2@NC-800催化HMF在50 ℃和常压氧气的条件下反应12 h后,得到产率为85%的DMFDCA。多孔催化剂的高比表面积提高了传质效率。Co纳米粒子(NPs)和呈原子级分散的Mn与掺杂在碳中的氮配位形成M―Nx。富含吡啶氮的碳基体中的缺电子金属位点有利于HMF和氧的活化。氧形成的超氧自由基阴离子的存在确保了半缩醛中间体和5-(羟基甲基)-2-糠酸甲酯(HMMF)的羟甲基的脱氢氧化,从而高选择性得到DMFDCA。该催化剂性能稳定,可适用于各种取代芳醇。该催化体系具有用于生产聚合物单体羧基酯的应用潜力。 相似文献
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藻红B、玫瑰红和3,5-二碘酪氨酸的催化动力学研究白亚丽,过玮,宋俊峰(西北大学电分析化学研究所,西安,710069)关键词藻红B,玫瑰红,3,5-二碘酪氨酸,催化动力学,单扫描示波极谱法碘催化As(3+)-Ce(4+)反应的现象被广泛应用于动力学测... 相似文献
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提出了高效液相色谱法测定玫瑰花中9种黄酮含量的方法。玫瑰花样品经甲醇-水(8+2)混合液高速匀浆提取,分取提取液5.0mL,经MCI-GEL反相树脂固相萃取小柱净化,取净化液2.00mL供色谱分析。用Waters Exterra色谱柱为分离柱,用甲醇和乙酸(0.5+99.5)溶液以不同比例混合的混合液为流动相进行梯度洗脱,在检测波长358nm处进行测定。9种黄酮在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在35~45μg·L-1之间。加标回收率在96.3%~106%之间,测定值的相对标准偏差(n=7)在1.8%~2.8%之间。 相似文献
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Surbhi Benjamin Dipti Vaya P.B. Punjabi Suresh C. Ameta 《Arabian Journal of Chemistry》2011,4(2):205-209
An attempt has been made to enhance the photocatalytic activity of zinc oxide semiconductor by coating it with extracts of natural pigments, chlorophyll and anthocyanin. Coated photocatalyst has been used for the photobleaching of rose bengal dye. Progress of the reaction has been monitored spectrophotometrically by measuring absorbance of the reaction mixture at definite time intervals. The effect of variation of different parameters such as pH, concentration of dye, amount of semiconductor and light intensity on the rate of photobleaching was also observed. A tentative mechanism for the reaction has been proposed. 相似文献
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The oxidation of 2-furoic acid to 5-hydroxy-5H-furan-2-one has been accomplished in quantitative yield in chloroform using a novel supported photocatalyst. This material comprises Rose Bengal grafted to the surface of a highly crosslinked polystyrene-divinylbenzene polymer, which was synthesized in a porous monolithic format. 相似文献
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Conrad Hans Eugster Edith Mrki-Fischer 《Angewandte Chemie (International ed. in English)》1991,30(6):654-672
In this article we present a survey of the pigments found in the flowers and fruits of old and modern varieties of roses. The yellow colors are produced by carotenoids, the reds by anthocyanins, and the modern oranges by a mixture of the two. The great structural diversity of the carotenoids contrasts with a surprisingly small number of anthocyanins. For the carotenoids found in roses, a clear correspondence exists between the structure and the breeding partners used; the old yellow roses, which arose from crosses with Chinese varieties, mainly contain carotenoids from early stages in the biosynthesis, while in the modern yellow roses, which are descended from Central Asian foetida types, hydroxylations, epoxidations, and epoxide transformations readily occur. A recently elucidated carotenoid degradation sequence follows the scheme C40 → C13 + C27 → C13 + C14. The C13 compounds are odoriferous substances that contribute to the scent of roses. In the physiological pH region, copigmentation with flavonol glycosides is crucial for stabilization of the anthocyanin chromophores. Many roses, including the “apothecary's rose”, which was once used medicinally, contain large amounts of strongly astringent ellagitannins, monosaccharide esters of gallic acid. 相似文献
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Fanbin Meng Yingqing Zhan Yajie Lei Rui Zhao Mingzhen Xu Xiaobo Liu 《European Polymer Journal》2011,(8):1563-1568
Novel rose thorns-like nanofibers, composed of polyarylene ether nitriles (PEN) “rose stems” and iron phthalocyanine (FePc) “thorns”, are prepared by combining electrospinning and controlled temperature-induced self-assembly. After removing solvent and subsequent temperature treatment, the FePc sheath structure changes from bead structure to rose thorns-like structure. The unique nanoscale architecture can be finely controlled by the processing time and temperature. The length of “thorns” on the “rose stems” can change from several nanometers to decade micrometers. The driving force for the morphology changes comes from self-assembly of FePc, including the π–π supramolecular interaction between aromatic cores and the cooperative complexation of metal ions between peripheral crown ether moieties. This novel structure, rendering a 3-D feature, can offer potential in a number of applications, including nanoelectronics. 相似文献
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Visible light active Ag doped SnO2 nanoparticles modified with curcumin (Cur–Ag–SnO2) have been prepared by a combined precipitation and chemical impregnation route. The optical properties, phase structures and morphologies of the as-prepared nanoparticles were characterized using UV–visible diffuse reflectance spectra (UV–vis-DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The surface area was measured by Brunauer. Emmett. Teller (B.E.T) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag–SnO2 and Cur–Ag–SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Cur–Ag–SnO2 shows better photocatalytic activity than that of Ag–SnO2 and SnO2. The superior photocatalytic activity of Cur–Ag–SnO2 could be attributed to the effective electron-hole separation by surface modification. The effect of photocatalyst concentration, initial dye concentration and electron scavenger on the photocatalytic activity was examined in detail. Furthermore, the antifungal activity of the photocatalysts and the reusability of Cur–Ag–SnO2 were tested. 相似文献
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以红玫瑰花瓣为模板, 用纳米压印图案转移法进行仿生合成, 获得具有多功能性的高分子薄膜. 通过将薄膜进行染色, 制得了具有特殊花瓣颜色的人工薄膜, 并探讨了化学色与结构色之间的关系. 相似文献
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Xiao-Qiang Dai Wen-Xiu Xu Ya-Long Wen Xing-Hai Liu Jian-Quan Weng 《Tetrahedron letters》2018,59(30):2945-2949
Metal and acid-free visible light-induced Friedel-Crafts C3-alkylation reactions of indole derivatives were developed using N,N-dimethylanilines as the carbon source. A cheap and readily available organic dye, Rose Bengal, was applied as the photocatalyst. This environmentally friendly transformation afforded C3-alkylated indoles in moderate to good yields under mild conditions. 相似文献
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Summary A strategy was developed which uses the adduct of ozone and triphenyl phosphite as a substitute for photochemically generated singlet oxygen in ene reactions of olefins. The resulting allylic hydroperoxide can be conveniently reduced by a second mole of phosphite to yield the corresponding allylic alcohol. The aryl phosphate produced as the by-product can either be recycled by reduction or used itself as a commodity. As an example, the two key steps of the rose oxide synthesis involving singlet oxygen can thus be reduced to a one pot procedure. With respect to the reaction mechanism, additional arguments for the direct reaction of the olefin with the phosphite ozonide were gathered. A simple decomposition of the ozonide to produce singlet oxygen was made rather unlikely.
Ozon als Sauerstoffquelle für En-Reaktionen von Olefinen
Zusammenfassung Es wurde eine Strategie zum Ersatz von photochemisch erzeugtem Singlett-Sauerstoff durch das Addukt aus Ozon und Triphenylphosphit zum Einsatz in En-Reaktionen von Olefinen entwickelt. Das entstehende allylische Hydroperoxid kann durch ein zweites Molekül Phosphit einfach zum entsprechenden allylischen Alkolhol reduziert werden. Das als Nebenprodukt entstehende Arylphosphat kann entweder durch Reduktion recycliert oder direkt als Handelsware weiterverwendet werden. Auf diese Weise können zum Beispiel die beiden Stufen der Rosenoxidsynthese, an denen Singlett-Sauerstoff beteiligt ist, zu einer Eintopfreaktion vereinfacht werden. Bezüglich des Reaktionsmechanismus wurden zusätzliche Hinweise auf die direkte Reaktion des Phosphitozonids mit dem Olefin gefunden. Eine Zersetzung des Ozonids unter Bildung von Singlettsauerstoff ist nicht wahrscheinlich.相似文献