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991.
Two novel [3]pseudorotaxanes can be selectively synthesized from four components through self-sorting processes, which provides a new strategy for the construction of a well-organized heteropolyrotaxane. 相似文献
992.
Mahmoud. Abd El Aleem. Ali. Ali. El-Remaily 《催化学报》2015,(7):1124-1130
A series of coumarin-chalcone hybrid compounds and coumarins linked to pyrazoline was synthe-sized in good yield and short time using a simple and efficient method. This method involved the one-pot reaction of salicylaldehyde, an α-ketoester and an aromatic aldehyde (in the case of the coumarin-chalcone derivatives) in addition to hydrazine hydrate (in the case of the pyrazolyl cou-marins) in the presence of a catalytic amount of bismuth triflate [Bi(OTf)3, 5 mol%]. The synthesized compounds showed scavenging activity towards the free radical 2,2-diphenyl-1-picrylhydrazyl. All compounds were characterized using IR,1H NMR and13C NMR spectroscopy. 相似文献
993.
994.
A simple and green method has been developed for the synthesis of 2-aminocyclohex-1-ene-1-carboxylic esters through a one-pot three-component condensation reaction of primary amines, ethyl acetoacetate and chalcones using FeCl3/SiO2 nanoparticles in ethanol. This method has several advantages such as high to excellent product yields in short time, using an inexpensive and reusable catalyst and available starting material. 相似文献
995.
Cutting‐edge mass spectrometry characterization of originator,biosimilar and biobetter antibodies 下载免费PDF全文
A. Beck F. Debaene H. Diemer E. Wagner‐Rousset O. Colas A. Van Dorsselaer S. Cianférani 《Journal of mass spectrometry : JMS》2015,50(2):ii-ii
The approval process for antibody biosimilars relies primarily on comprehensive analytical data to establish comparability and high similarity with the originator. Mass spectrometry (MS) in combination with liquid chromatography (LC) and electrophoretic methods are the corner stone for comparability and biosimilarity evaluation. In this special feature we report head‐to‐head comparison of trastuzumab and cetuximab with corresponding biosimilar and biobetter candidates based on cutting‐edge mass spectrometry techniques such as native MS and ion‐mobility MS at different levels (top, middle and bottom). In addition, we discuss the advantages and the limitations of sample preparation and enzymatic digestion, middle‐up and ‐down strategies and the use of hydrogen/deuterium exchange followed by MS (HDX‐MS). Last but not least, emerging separation methods combined to MS such as capillary zone electrophoresis‐tandem MS (CESI‐MS/MS), electron transfer dissociation (ETD), top down‐sequencing (TDS) and high‐resolution MS (HR‐MS) that complete the panel of state‐of‐the‐art MS‐based options for comparability and biosimilarity evaluation are presented. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
996.
Interrupted Pummerer Reaction in Latent‐Active Glycosylation: Glycosyl Donors with a Recyclable and Regenerative Leaving Group 下载免费PDF全文
Penghua Shu Xiong Xiao Yueqi Zhao Yang Xu Wang Yao Jinyi Tao Hao Wang Prof. Dr. Guangmin Yao Prof. Dr. Zimin Lu Prof. Dr. Jing Zeng Prof. Dr. Qian Wan 《Angewandte Chemie (International ed. in English)》2015,54(48):14432-14436
Latent O‐glycosides, 2‐(2‐propylthiol)benzyl (PTB) glycosides, were converted into the corresponding active glycosyl donors, 2‐(2‐propylsulfinyl)benzyl (PSB) glycosides, by a simple and efficient oxidation. Treatment of the PSB donor and various acceptors with triflic anhydride provided the desired glycosides in good to excellent yields. The leaving group, which was activated by an interrupted Pummerer reaction, can be recycled (PSB‐OH) and regenerated as the precursor (PTB‐OH). A natural hepatoprotective glycoside, leonoside F, was efficiently synthesized in a convergent [3+1] manner with this newly developed method. The present total synthesis also led to a structural revision of this phenylethanoid glycoside. 相似文献
997.
998.
Acid-controlled, chemodivergent and redox-neutral annulations for the synthesis of isocoumarins and isoquinolinones have been realized via Rh(III)-catalyzed CH activation. Diazo compounds act as a carbene precursor, and coupling occurs in one-pot process, where adipic acid and trimethylacetic acid promote chemodivergent cyclizations. 相似文献
999.
In many reactions involving selenosulfonate or thiosulfonate,the sutfone group often leaves in form of benzenesutfinic acid or sodium benzenesulfinate.A one-pot two-step reaction of selenosulfonate with isocyanides and allyl alcohol under aqueous conditions to afford selenocarbamates and allyl sulfone compounds is reported.The sulfinic acid as the first-step side product is converted to the allyl sulfone compound by water promoted reaction with allyl alcohol.Water acts as both an oxygen source of selenocarbamates and as a promoter to drive the second step reactio n.The reactions have the advantages of mild conditions,green,environment-friendly,and high atomic economy. 相似文献
1000.
Lemonomycin (1) was first isolated from the fermentation broth of Streptomyces candidus in 1964. The complete chemical structure was not elucidated until 2000 with extensive spectroscopic analysis. Lemonomycin is currently known as the only glycosylated tetrahydroisoquinoline antibiotic. Its potent antibacterial activity against Staphylococcus aureus and Bacillus subtilis and complex architecture make it an ideal target for total synthesis. In this short review, we summarize the research status of lemonomycin for biological activity, biosynthesis, and chemical synthesis. The unique deoxy aminosugar-lemonose was proposed to play a crucial role in biological activity, as shown in other antibiotics, such as arimetamycin A, nocathiacin I, glycothiohexide α, and thiazamycins. Given the self-resistance of the original bacterial host, the integration of biosynthesis and chemical synthesis to pursue efficient synthesis and further derivatization is in high demand for the development of novel antibiotics to combat antibiotic-resistant infections. 相似文献