25252-64-6Relevant articles and documents
Osmium Catalysts for Acceptorless and Base-Free Dehydrogenation of Alcohols and Amines: Unusual Coordination Modes of a BPI Anion
Buil, María L.,Esteruelas, Miguel A.,Gay, M. Pilar,Gómez-Gallego, Mar,Nicasio, Antonio I.,O?ate, Enrique,Santiago, Alicia,Sierra, Miguel A.
, p. 603 - 617 (2018/03/08)
A novel type of catalyst precursors for the dehydrogenation of hydrogen carriers based on organic liquids has been discovered. Complexes OsH6(PiPr3)2 (1) and OsH(OH)(CO)(PiPr3)2 (2) react with 1,3-bis(6′-methyl-2′-pyridylimino)isoindoline (HBMePI) to give OsH3{κ2-Npy,Nimine-(BMePI)}(PiPr3)2 (3) and OsH{κ2-Npy,Nimine-(BMePI)}(CO)(PiPr3)2 (4). The unprecedented κ2-Npy,Nimine coordination mode of BMePI is thermodynamically preferred with Os(IV) and Os(II) metal fragments and allows for preparation of BMePI-based dinuclear metal cations. Treatment of OsH2Cl2(PiPr3)2 (5) with 0.5 equiv of HBMePI in the presence of KOtBu affords the chloride salt of the bis(osmium(IV)) dinuclear cation [{OsH3(PiPr3)2}2{μ-(κ2-Npy,Nimine)2-BMePI}]+ (6). Related homoleptic bis(osmium(II)) complexes have been also synthesized. Complex 4 reacts with the bis(solvento) [OsH(CO){κ1-O-[OCMe2]2}(PiPr3)2]BF4 to give [{OsH(CO)(PiPr3)2}2{μ-(κ2-Npy,Nimine)2-BMePI}]BF4 (7), whereas the addition of 0.5 equiv of HBMePI to {OsCl(η6-C6H6)}2(μ-Cl)2 (8) affords [{OsCl(η6-C6H6)}2{μ-(κ2-Npy,Nimine)2-BMePI}]Cl (9). The reactions of 4 with 8 and {OsCl(η6-p-cymene)}2(μ-Cl)2 (10) lead to the heteroleptic cations [(PiPr3)2(CO)HOs{μ-(κ2-Npy,Nimine)2-BMePI}OsCl(η6-arene)]+ (arene = C6H6 (11), p-cymene (12)). The electronic structrure and electrochemical properties of the dinuclear complexes were also studied. Complexes 3 and 4 are efficient catalyst precursors for the acceptorless and base-free dehydrogenation of secondary and primary alcohols and cyclic and lineal amines. The primary alcohols afford aldehydes. The amount of H2 released per gram of heterocycle depends upon the presence of a methyl group adjacent to the nitrogen atom, the position of the nitrogen atom in the heterocycle, and the size of the heterocycle.
Preparation method of 1-(tetrahydrofuran-2-yl) ethanone
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Paragraph 0022; 0023; 0024; 0025, (2017/09/02)
The invention discloses a preparation method of 1-(tetrahydrofuran-2-yl) ethanone and belongs to the field of medical technologies and chemistry. The preparation method comprises steps as follows: tetrahydrofuroic acid serving as a raw material and malonic acid cyclic isopropylidene ester are subjected to a condensation reaction in a system of a condensing agent, alkali and an organic solvent and then subjected to a hydrolysis reaction under the catalysis of acid, and a target product is obtained. According to the method, a Grignard reagent, thionyl chloride and other reagents with high potential safety hazard and high corrosiveness are not required to be used, harsh high-temperature and high-pressure reaction conditions are not required, and the safety and environmental protection pressure is small; with the system of the condensing agent and alkali, an intermediate is prepared under the condition of room temperature with a one-pot method, and problems such as long steps, high energy consumption, difficulty in pH value control due to stepwise reactions in the prior art are solved, aftertreatment operation is simple, few byproducts are produced and easy to remove, a solvent can be recycled and reused, and the yield is increased to 90% or higher under the condition that the chemical purity of a product is 98% or above.
Industrial preparation method of acetyl tetrahydrofuran with high optical purity
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Paragraph 0011; 0031, (2016/10/08)
The invention discloses an industrial preparation method of acetyl tetrahydrofuran with a high optical purity, and belongs to the field of chemical synthesis. According to the preparation method, tetrahydrofuroic acid is taken as the raw material and then is chlorinated to obtain tetrahydrofuran carbonyl chloride, tetrahydrofuran carbonyl chloride and Meldrum's acid carry out condensation reactions, and reaction product is hydrolyzed to obtain the target compound namely acetyl tetrahydrofuran. The preparation method has the advantages that the raw material cost is low, the preparation method does not need any Grignard reagent, the product property is stable, the purity can reach 98% or more, the optical purity can reach 99% or more, and the yield can reach 70% or more. The method has applied to industrial production. The product quality is stable. The reaction conditions are mild. The operation is safe and reliable. Dichloromethane can be recycled. The technology has the advantages of good repeatability and low preparation cost, and is a reliable industrial production method of acetyl tetrahydrofuran with a high optical purity.
