- Environmentally responsible, safe, and chemoselective catalytic hydrogenation of olefins: ppm level Pd catalysis in recyclable water at room temperature
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Textbook catalytic hydrogenations are typically presented as reactions done in organic solvents and oftentimes under varying pressures of hydrogen using specialized equipment. Catalysts new and old are all used under similar conditions that no longer reflect the times. By definition, such reactions are both environmentally irresponsible and dangerous, especially at industrial scales. We now report on a general method for chemoselective and safe hydrogenation of olefins in water using ppm loadings of palladium from commercially available, inexpensive, and recyclable Pd/C, together with hydrogen gas utilized at 1 atmosphere. A variety of alkenes is amenable to reduction, including terminal, highly substituted internal, and variously conjugated arrays. In most cases, only 500 ppm of heterogeneous Pd/C is sufficient, enabled by micellar catalysis used in recyclable water at room temperature. Comparison with several newly introduced catalysts featuring base metals illustrates the superiority of chemistry in water.
- Gallou, Fabrice,Gao, Eugene S.,Lipshutz, Bruce H.,Takale, Balaram S.,Thakore, Ruchita R.
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supporting information
p. 6055 - 6061
(2020/10/14)
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- Synthesis method of promestriene
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The invention relates to a synthesis method of compound promestriene. The compound is a derivative of estradiol, has characteristics of estrogen and has a significant effect of regulating and promoting normal development of female sexual organs and secondary sexual characteristics. Estradiol is used as a starting material, sodium hydroxide is adopted for base catalysis and subjected to a reactionwith n-bromopropane in an acetone solvent, and 3-propoxy-17beta-hydroxyestr-1,3,5(10)-triene is prepared; promestriene is prepared from sodium hydride as an alkaline catalyst and methyl iodide as a methylation reagent in a tetrahydrofuran solvent. The synthesis method has the advantages that reaction conditions are mild, toxicity of the solvents or reagents is low, post-treatment is convenient, the yield is high and synthesis cost is low, and the synthesis method is environmentally friendly.
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Paragraph 0022-0024
(2019/07/29)
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- Enhanced Reactivity of Aerobic Diimide Olefin Hydrogenation with Arylboronic Compounds: An Efficient One-Pot Reduction/Oxidation Protocol
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A catalyst-free and efficient method for simultaneous olefin hydrogenation and oxidation of arylboronate esters to phenols with hydrazine hydrate and molecular oxygen is presented. The process is based on the utilization of a readily available Lewis acidic arylboron compound, which evades common problems associated with the catalyst-free aerobic hydrogenation of olefins with diimide. Using an operationally simple procedure, the protocol smoothly delivers phenol derivatives and various alkanes in excellent yields with remarkable functional group compatibility. The method allows the reaction to be scaled up to 1 g of the starting materials.
- Santra, Surojit,Guin, Joyram
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supporting information
p. 7253 - 7257
(2015/11/25)
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- Rearrangement and fragmentation of estrogen ether ions: New aspects found with Fourier transform ion cyclotron resonance mass spectrometry
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Electrospray ionization mass spectra of several di- and tri-hydroxy-estratriene-ethers, as well as estradiol and estriol, have been investigated by high-resolution mass spectrometry. The fragmentation mechanisms leading to the loss of water molecules from the protonated molecular ion have been rationalized by using protecting groups as well as mass spectrometric means such as collision-induced dissociation and infrared multi-photon dissociation. The unexpected observation of a simultaneous loss of two water molecules from the protonated estradiol ethers and of three water molecules from the protonated estriol ethers has been discussed with respect to varying reaction mechanisms and rearrangements. Results and conclusions derived from them were obtained by adequate deuterated ethers.
- Freudenhammer, Christoph,Grotemeyer, Juergen
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experimental part
p. 489 - 501
(2011/10/31)
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- Oestratriene diethers
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3,17-Estratriene diethers, useful as anti-seborrheic and gynecological agents, is described.
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