The 3D structure of the super-sauze earthflow: A first stage towards modelling its behaviour
摘要:
In the "Terres-Noires" of the Barcelonnette basin, France, the Super-Saute earthflow is being studied to understand the mechanisms of triggering, slidding and flowing and to propose a predicting dynamic behaviour model. This paper describes the main results of an on-site geotechnical investigation carried out in 1996, which allowed us to establish precisely the internal 3-D structure of the moving mass (position and shape of the paleotopography, functioning of two flow units from the surface to the depth and spatial subdivision of the flow into. compartments using contrasts of velocity, by morphological aspects, or mechanical and hydrodynamical characteristics of the material). Moreover, studies of old aerial photographs identified the importance of the buried topography on the dynamic evolution of the flow. (C) 2000 Elsevier Science Ltd. All rights reserved.
[3+1+1] type cyclization of ClCF<sub>2</sub>COONa for the assembly of imidazoles and tetrazoles <i>via in situ</i> generated isocyanides
作者:Ya Wang、Yao Zhou、Qiuling Song
DOI:10.1039/d0cc01919d
日期:——
A facile synthesis of imidazoles and tetrazoles via [3+1+1] type cyclization of ClCF2COONa is developed. A diverse array of imidazoles and tetrazoles were obtained in decent yields via isocyanide intermediates. Notably, this is the first example of the cycloaddition of in situ generated isocyanides.
Regioselective Copper-Catalyzed Amination of Chlorobenzoic Acids: Synthesis and Solid-State Structures of <i>N</i>-Aryl Anthranilic Acid Derivatives
作者:Xuefeng Mei、Adam T. August、Christian Wolf
DOI:10.1021/jo0518809
日期:2006.1.1
amination of 2-chlorobenzoic acids with aniline derivatives has been developed. The method eliminates the need for acid protection and produces a wide range of N-aryl anthranilic acid derivatives in up to 99% yield. The amination was found to proceed with both electron-rich and electron-deficient aryl chlorides and anilines and also utilizes sterically hindered anilines such as 2,6-dimethylaniline and
The Brønsted acid-catalyzedsynthesis of primary amines from acetyl arenes and alkanes with C–C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction
Encapsulation of Pd(II) into superparamagnetic nanoparticles grafted with EDTA and their catalytic activity towards reduction of nitroarenes and Suzuki-Miyaura coupling
Fe3O4@EDTA–Pd(II) was screened for the Suzuki reaction and reduction of nitrocompounds in water. The Pd content of the catalyst was measured to be 0.28 mmol Pd g−1. In addition, the Fe3O4@EDTA–Pd catalyst can be easily separated and recovered with an external permanent magnet. The anchored solid catalyst can be recycled efficiently and reused five times with only a very slight loss of catalytic activity
A newtype of amino amide organocatalysts was designed and synthesized from commercially available amino acids in easy steps. Their catalytic activities were examined in enantioselective crossed aldol reaction of various acyclic and cyclic ketones with aromaticaldehydes to afford the corresponding chiral anti-aldol adducts with good to excellent chemical yields, diastereoselectivities and enantioselectivities