26574-26-5Relevant academic research and scientific papers
Preparation method of hydroxyl ketone compound
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Paragraph 0037-0038, (2020/07/12)
The invention discloses a preparation method of a hydroxyl ketone compound. The method comprises a step of converting dihydric alcohol into a hydroxyl ketone compound in the presence of a copper-basedcatalyst, namely a conversion step, and the reaction conditions of the conversion step are as follows: the reaction temperature is 200-400 DEG C, the reaction pressure is 0.01-0.5 MPa, and the liquidhour space velocity is 0.1-10 h. The method has a high raw material conversion rate and high selectivity of the hydroxyl ketone compound with terminal hydroxyl, and is easy to implement industrially.
Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound i Type Oxidants
Bugnola, Marco,Shen, Kaiji,Haviv, Eynat,Neumann, Ronny
, p. 4227 - 4237 (2020/05/05)
The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various "shunt" pathways, have shown that high-valent Fe(V)=O and the formally isoelectronic Fe(IV) =O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron-tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom ("NIH shift"); (2) a high kinetic isotope effect for alkyl C - H bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.
Porphyrins with exocyclic rings. Part 12. Synthesis of meso,β-butano- and meso,β-pentanoporphyrins from cycloalka[b]pyrroles
Bastian, Jolie A.,Lash, Timothy D.
, p. 6299 - 6310 (2007/10/03)
Pyrroles 5 with b-face fused seven- or eight-membered carbocyclic rings were prepared in good yields by Knorr-type condensations with cycloheptanone or cyclooctanone, respectively. Treatment with lead tetraacetate in dichloromethane afforded the labile ω-acetates 8 and subsequent acid catalyzed condensation with α-unsubstituted pyrrole-2-carboxylates yielded the related pyrrolylcycloalka[b]pyrroles 29 and 30. The α-unsubstituted pyrroles 14 and 23 were prepared by condensing α,β-unsubstituted ketones, or their β-acetoxycarbonyl precursors, with benzyl N-tosylglycinate in the presence of DBU, followed by dehydration with POCl3-pyridine and base catalyzed elimination of p-toluenesulfinic acid. Dipyrrole dibenzyl esters 29 and 30 were hydrogenolysed over 10% Pd-C to give the corresponding dicarboxylic acids. Acid catalyzed condensation with diformyldipyrrylmethane 33 under modified MacDonald '2 + 2' conditions afforded a series of four cycloalkanoporphyrins 4a-d with seven- or eight-membered exocyclic rings. Although the meso,β-butanoporphyrins 4a and 4b were isolated in good yields, poorer results were obtained for the related meso,β-pentanoporphyrin: 4c and 4d. It is proposed that the eight-membered carbocyclic ring distorts the geometry of the open-chain tetrapyrrolic intermediates and this deleterious influence results in the lower yields observed.
