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A Native Chemical Ligation Handle that Enables the Synthesis of Advanced Activity‐Based Probes: Diubiquitin as a Case Study 下载免费PDF全文
Dr. Monique P. C. Mulder Dr. Farid El Oualid Jarno ter Beek Prof. Dr. Huib Ovaa 《Chembiochem : a European journal of chemical biology》2014,15(7):946-949
We present the development of a native chemical ligation handle that also functions as a masked electrophile that can be liberated during synthesis when required. This handle can thus be used for the synthesis of complex activity‐based probes. We describe the use of this handle in the generation of linkage‐specific activity‐based deubiquitylating enzyme probes that contain substrate context and closely mimic the native ubiquitin isopeptide linkage. We have generated activity‐based probes based on all seven isopeptide‐linked diubiquitin topoisomers and demonstrated their structural integrity and ability to label DUBs in a linkage‐specific manner. 相似文献
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Soichiro Kawamorita Kenji Yamazaki Hirohisa Ohmiya Tomohiro Iwai Masaya Sawamura 《Advanced Synthesis \u0026amp; Catalysis》2012,354(18):3440-3444
A silica‐supported, cage‐type, compact phosphane (Silica‐SMAP) was used for the copper‐catalyzed conjugate reduction of α,β‐unsaturated carbonyl and carboxyl compounds with poly(methylhydrosiloxane) (PMHS). The heterogeneous catalyst system showed high activity and chemoselectivity, and was easily separable from the reaction mixture after the reaction. Furthermore, the catalyst was reusable without loss of its high catalytic activity or selectivity. 相似文献
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Claudia Sorbi Dr. Silvia Franchini Dr. Annalisa Tait Prof. Adolfo Prandi Dr. Rossella Gallesi Piero Angeli Prof. Gabriella Marucci Prof. Lorenza Pirona Dr. Elena Poggesi Dr. Livio Brasili Prof. 《ChemMedChem》2009,4(3):393-399
Conformational restriction of naftopidil led to the discovery of a new class of ligands with a 1,3‐dioxolane (1,3‐oxathiolane, 1,3‐dithiolane) structure that bind to α1 adrenoceptor subtypes and 5‐HT1A receptors. Adequate structural modifications address the selectivity toward one or the other receptor system.
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R. Ballini L. Barboni L. Castrica F. Fringuelli D. Lanari F. Pizzo L. Vaccaro 《Advanced Synthesis \u0026amp; Catalysis》2008,350(9):1218-1224
2‐tert‐Butylimino‐2‐diethylamino‐1,3‐dimethylperhydro‐1,3,2‐diazaphosphorine supported on polystyrene (PS‐BEMP) is an efficient catalyst for the addition of nitroalkanes (1–1.5 equiv.) to α,β‐unsaturated carbonyl compounds (1.0 equiv.) in the absence of a reaction medium (solvent‐free conditions). The corresponding γ‐nitro carbonyl compounds have been isolated in excellent yields but the catalyst can be satisfactorily recovered and used for only 3 times due to the magnetic stirring which caused crunching of the catalyst beads thus hampering its complete recovery. To optimize the catalyst’s reuse and improve the environmental efficacy of solvent‐free conditions, the first solvent‐free cyclic continuous‐flow reactor has been set up. This reactor has allowed the product to be isolated in an almost quantitative yield by using a very small amount of organic solvent, making the recovery and reuse of the catalyst efficient and reproducible. 相似文献
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Shun‐Yi Wang Ping Song Teck‐Peng Loh 《Advanced Synthesis \u0026amp; Catalysis》2010,352(18):3185-3189
The role of excess ligand in the asymmetric 1,4‐conjugate addition (ACA) of Grignard reagents to α,β‐unsaturated esters compounds catalyzed by copper(I) iodide‐2,2′‐bis(di‐p‐tolylphosphino)‐1,1′‐binaphthyl (CuI‐Tol‐BINAP) is explored herein. In addition, this methodology allows asymmetric induction to be carried out using a non‐chiral phosphine copper complex with excess of a chiral phosphine ligand. 相似文献
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Wen‐Xing Liu Si‐Kai Chen Jin‐Miao Tian Yong‐Qiang Tu Shao‐Hua Wang Fu‐Min Zhang 《Advanced Synthesis \u0026amp; Catalysis》2015,357(18):3831-3835
A series of new water‐compatible “spiropyrrolidine triazole” catalysts was designed and synthesized. The asymmetric Michael addition of nitromethane and α,β‐unsaturated aldehydes in an aqueous system was investigated to evaluate these new catalysts, and the resulting adducts were obtained with excellent enantioselectivity (up to 95.5% ee) and moderate to good yield (63–88%).
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Yanmei Liu Hua Lai Bo Rong Tie Zhou Jia Hong Chao Yuan Shujing Zhao Xiaolong Zhao Biao Jiang Qiang Fang 《Advanced Synthesis \u0026amp; Catalysis》2011,353(17):3161-3165
An efficient strategy for a high‐yielding and stereoselective synthesis of α‐trifluoromethyl unsaturated carboxylic acids directly from the reactions of 3,3,3‐trifluoropropanoic acid (CF3CH2COOH) with various aryl aldehydes in the presence of titanium tetrachloride (TiCl4) is reported here for the first time, which is a valuable expansion for the classical Knoevenagel reaction. Because these compounds may have potential applications in organic electronics and can be easily converted to the corresponding fluorinated alcohols and amino acids with excellent bioactivity, this route should be a good choice for the preparation of α‐trifluoromethyl‐containing derivatives. 相似文献
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Jonathan Wong Kennard Gan Houguang Jeremy Chen Sumod A. Pullarkat 《Advanced Synthesis \u0026amp; Catalysis》2014,356(16):3391-3400
The asymmetric conjugate 1,4‐addition of arylboronic acids to α,β‐unsaturated carbonyl compounds is an extremely versatile and widely used organic transformation. While the rhodium(I)‐catalysed reaction has been thoroughly explored, the asymmetric palladium‐catalysed protocol is far less developed and understood, particularly with acyclic enones as substrates. Herein, we report the systematic evaluation of a series of metallacycles for this reaction and the conjugate addition of arylboronic acids to a wide range of α,β‐unsaturated enones, catalysed by an easily accessible and robust chiral phosphapalladacycle in high yields and enantioselectivities.
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Solution NMR Studies of Recombinant Aβ(1–42): From the Presence of a Micellar Entity to Residual β‐Sheet Structure in the Soluble Species 下载免费PDF全文
Marielle Aulikki Wälti Julien Orts Beat Vögeli Silvia Campioni Roland Riek 《Chembiochem : a European journal of chemical biology》2015,16(4):659-669
Amyloid‐β (Aβ) peptide is the major component found in senile plaques of Alzheimer's disease patients. The 42‐residue fragment Aβ(1–42) is proposed to be one of the most pathogenic species therein. Here, the soluble Aβ(1–42) species were analyzed by various liquid‐state NMR methods. Transient formation of a micelle species was observed at the onset of the aggregation kinetics. This micelle is dissolved after approximately one day. Subsequent loss of this species and the formation of protofibrils are proposed to be the route of fibril formation. Consequently, the observed micelle species is suggested to be on an off‐pathway mechanism. Furthermore, characterization of the NMR‐observable soluble species shows that it is a random‐coil‐like entity with low propensities for four β‐strands. These β‐strands correlate with the β‐strand segments observed in Aβ fibrils. This finding indicates that the 3D structure of the fibrils might already be predisposed in the soluble species. 相似文献
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Cold‐pressed Japanese quince (Chaenomeles japonica (Thunb.) Lindl. ex Spach) seed oil as a rich source of α‐tocopherol,carotenoids and phenolics: A comparison of the composition and antioxidant activity with nine other plant oils 下载免费PDF全文
Paweł Górnaś Aleksander Siger Karina Juhņeviča Gunārs Lācis Elga Šnē Dalija Segliņa 《European Journal of Lipid Science and Technology》2014,116(5):563-570