排序方式: 共有12条查询结果,搜索用时 15 毫秒
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Saladino R Neri V Crestini C Costanzo G Graciotti M Di Mauro E 《Journal of the American Chemical Society》2008,130(46):15512-15518
We describe the one-pot synthesis of a large panel of nucleic bases and related compounds from formamide in the presence of iron sulfur and iron-copper sulfur minerals as catalysts. The major products observed are purine, 1H-pyrimidinone, isocytosine, adenine, 2-aminopurine, carbodiimide, urea, and oxalic acid. Isocytosine and 2-aminopurine may recognize natural nucleobases by Watson-Crick and reverse Watson-Crick interactions, thus suggesting novel scenarios for the origin of primordial nucleic acids. Since the major problem in the origin of informational polymers is the instability of their precursors, we also investigate the effects of iron sulfur and iron-copper sulfur minerals on the stability of ribooligonucleotides in formamide and in water. All of the iron sulfur and iron-copper sulfur minerals stimulated degradation of RNA. The relevance of these findings with respect to the origin of informational polymers is discussed. 相似文献
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Indole-2-one derivatives were prepared from the corrisponding isatines via one pot reduction in hydrazine hydrate. 相似文献
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Giurlani Walter Sergi Luca Crestini Eugenio Calisi Nicola Poli Federico Soavi Francesca Innocenti Massimo 《Journal of Solid State Electrochemistry》2022,26(1):85-95
Journal of Solid State Electrochemistry - The electrochemical behaviour of steel, copper, and titanium current collectors was studied in aqueous solutions of lithium... 相似文献
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The reactivity of methyltrioxorhenium in the epoxidation of olefins can be tuned by the presence of Lewis bases as ligands of the metal center. Unfortunately, a large excess of ligand is usually required to obtain high yields and selectivities mainly because of the fluxional behaviour that these compounds show in solution. We describe here the microencapsulation technique that can resolve this problem. Microencapsulated Lewis base adducts of methyltrioxorhenium with nitrogen containing ligands are highly efficient and selective catalysts for the epoxidation of several olefins and monoterpenes with hydrogen peroxide even in the case of the most sensitive substrates. These systems show the advantages of the ligand accelerated catalysis and the benefits of heterogeneous compounds. They can be easily recovered from the reaction mixture and used for more transformations. 相似文献
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Sette M Wechselberger R Crestini C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(34):9529-9535
Quick quantitative HSQC (QQ‐HSQC) was applied to quantitative evaluation of different inter‐unit linkages in an array of milled softwood and hardwood and technical lignins by using the guaiacyl C2 and syringyl C2–C6 signals as internal standards. The results were found to be highly reproducible and comparable with earlier literature reports. The advantage of QQ‐HSQC NMR analysis of lignin is contemporary detection and quantification of lignin inter‐unit linkages with a direct, non‐destructive method requiring short acquisition times. 相似文献
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Raffaele Saladino Claudia Crestini Francesca Occhionero Rosario Nicoletti 《合成通讯》2013,43(17):3241-3251
2-Mercaptoheterazoles readily react with ozone in the presence of nucleophiles and under mild experimental conditions to form several C-2 substituted heterazoles. 相似文献
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Gianluca Bianchini Marcello Crucianelli Carmen Canevali Claudia Crestini Franca Morazzoni Raffaele Saladino 《Tetrahedron》2006,62(52):12326-12333
Polymer-supported methyltrioxorhenium (MTO) systems are efficient catalysts for the oxidative functionalisation of cyclohexane and cyclopentane derivatives with H2O2 as oxygen donor. Using poly(4-vinyl)pyridine and poly(4-vinyl)pyridine-N-oxide as MTO supports, cycloalkanol, cycloalkanediol, cycloalkanone and ω-hydroxy methyl ketone derivatives were obtained in different yields depending on the experimental conditions. Interestingly, cycloalkane dimers were selectively recovered in acceptable to good yields when the oxidation was performed with polystyrene-microencapsulated MTO catalyst. The EPR investigation suggests that the homolytic cleavage of the CH3–Re bond with formation of CH3 radicals occurs inside the polystyrene capsule, indicating a possible role of methyl radical in the cycloalkane dimerisation pathway. 相似文献