2575-20-4Relevant academic research and scientific papers
Pinacol-Pinacolone Rearrangement Promoted by Polyphosphoric Acid Trimethylsilyl Ester (PPSE)
Kakimoto, Masa-aki,Seri, Takuya,Imai, Yoshio
, p. 2643 - 2644 (1988)
Pinacols afforded the corresponding pinacolones in high yields in the presence of the polyphosphoric acid trimethylsilyl ester (PPSE) at a temperature above 80 deg C.Tetraphenylethylene oxide, in addition to benzopinacolone, was obtained in the reaction of benzopinacol under milder conditions.The solvent effect suggested that the rearrangement proceeded via the carbonium-ion intermediate.
Method for preparing substituted carbonyl compound by catalyzing pinacol rearrangement reaction through molecular sieve
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Paragraph 0033-0038, (2020/09/12)
The invention discloses a method for preparing a substituted carbonyl compound by catalyzing pinacol rearrangement reaction through a molecular sieve. The method is characterized in that substituted pinacol as a substrate and toluene as solvent are subjected to a rearrangement reaction for 2-5h under the catalysis of an MCM-41, SBA-15, USY, Beta ZSM-5 or other aluminum-containing H-type acidic molecular sieve, the reaction temperature is 80-110 DEG C, the mass ratio of the substituted pinacol to the toluene to the catalyst is 100: 100: (10-50), the catalyst is filtered out after the reaction is finished, and purifying is performed to obtain a product, namely, the substituted carbonyl compound. Compared with the prior art, the method provided by the invention has the advantages of wide substrate application range, cheap catalyst, easy preparation, stability, no pollution to the environment, recyclability, realization of gram-scale preparation, and high reaction yield.
Silica-supported orthophosphoric acid (OPA/SiO2): preparation, characterization, and evaluation as green reusable catalyst for pinacolic rearrangement
Billamboz, Muriel,Banaszak, Estelle
, p. 1029 - 1040 (2019/04/10)
In this paper, we report an easy-to-prepare, cost-effective, efficient, and reusable silica-supported orthophosphoric acid (OPA) catalyst for pinacolic rearrangement. The surface properties of this catalyst were successfully characterized with the help of 31P NMR, TGA, DSC, FT-IR, titration, and microscopy. OPA, hydrogen bonded on the surface, is actually the active species and the reaction seems to occur in the liquid phase embedded in the silica support. As a consequence, the extracting solvent should be chosen with cautious to guarantee the recyclability of the catalyst. As example, pinacol rearrangement reactions were successfully realized with this catalyst and OPA/SiO2 proved to be as efficient as homogeneous orthophosphoric acid to promote the reaction of pinacol derivatives. When using dichloromethane as extracting solvent, OPA/SiO2 can be reuse up to ten times without a significant loss of activity. After ten runs, no physical damage of the catalyst has been observed by microscopy proving its suitability for such application.
Solvent free facile room temperature reduction of aromatic carbonyl and nitro compounds by zn/Conc. HCl system - An experimental and DFT study
Rajamathe,Bhuvaneswari
, p. 639 - 644 (2018/02/09)
This experimental and DFT studies involve a novel technique for the reduction of aromatic carbonyl/nitro compounds to the corresponding alcohols/amines, in high yield under laboratory conditions. The reducing species is the nascent hydrogen generated by the Zn/HCl system. The novelty of this work is that the comparison of yield with and without solvent. The yield is increased by many folds in the solvent free method compared to the solvent method reported earlier. The technique followed is to make a 'slurry' of the substrate with zinc dust (zinc slurry) and to add (in small portion of the dry slurry) to the optimized amount of conc. HCl, over a period of 3 to 4 h at room temperature. In this technique the substrate, adsorbed on zinc dust being very proximal to the site of generation nascent hydrogen, the reduction is very effective and the yield is high. The novelty is that zinc dust acts as catalyst (adsorbent role) and reactant (hydrogen generation role). The DFT study with B3LYP/6.311g ++ (d,p) basis set revealed that the stability of first formed free radical (energy factor) and the homo nuclear nature of carbonyl and nitro group (charge factor) decide the yield. The electrostatic potential calculated by DFT studies correlates well with Mullikan charges in deciding the charge factor. The free radical mechanism was confirmed by the formation of pinacol coupled product in one instance.
Lewis Acid Assisted Electrophilic Fluorine-Catalyzed Pinacol Rearrangement of Hydrobenzoin Substrates: One-Pot Synthesis of (±)-Latifine and (±)-Cherylline
Shi, Hui,Du, Chuan,Zhang, Xinhang,Xie, Fukai,Wang, Xiaoyu,Cui, Shanshan,Peng, Xiaoshi,Cheng, Maosheng,Lin, Bin,Liu, Yongxiang
, p. 1312 - 1319 (2018/02/09)
A microwave-irradiated solvent-free pinacol rearrangement of hydrobenzoin substrates catalyzed by a combination of N-fluorobenzenesulfonimide and FeCl3·6H2O was developed. Its selectivity was first investigated by density functional theory (DFT) calculations. Then the functional group tolerance was examined by synthesizing a series of substrates designed based on the insight provided by the DFT calculations. The application of the methodology was demonstrated by the efficient one-pot synthesis of (±)-latifine and (±)-cherylline, both are 4-aryltetrahydroisoquinoline alkaloids isolated from Amaryllidacecae plants.
Pinacol Rearrangement and Direct Nucleophilic Substitution of Allylic Alcohols Promoted by Graphene Oxide and Graphene Oxide CO2H
Gómez-Martínez, Melania,Baeza, Alejandro,Alonso, Diego A.
, p. 1032 - 1039 (2017/03/27)
Graphene oxide (GO) and carboxylic acid functionalized GO (GO–CO2H) have been found to efficiently promote the heterogeneous and environmentally friendly pinacol rearrangement of 1,2-diols and the direct nucleophilic substitution of allylic alcohols. In general, high yields and regioselectivities are obtained in both reactions using 20 wt % of catalyst loading and mild reaction conditions.
A gold catalytic pinacone method of rearrangement of
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Paragraph 0047; 0048; 0049; 0050; 0051, (2017/11/22)
The invention provides a method used for catalytic rearrangement of pinacol with gold. A reaction general formula is disclosed in the invention, wherein R1, R2, R3, and R4 may be common alkyl, cycloalkyl, and aromatic rings. A gold catalyst needed by reac
PICOLINAMIDE COMPOUNDS WITH FUNGICIDAL ACTIVITY
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Paragraph 0084, (2016/08/23)
This disclosure relates to picolinamides of Formula I and their use as fungicides. Fungicides are compounds, of natural or synthetic origin, which act to protect and/or cure plants against damage caused by agriculturally relevant fungi. Generally, no single fungicide is useful in all situations. Consequently, research is ongoing to produce fungicides that may have better performance, are easier to use, and cost less.
An alternative reaction outcome in the gold-catalyzed rearrangement of 1-alkynyloxiranes
Gonzalez, Maria J.,Gonzalez, Jesus,Vicente, Ruben
supporting information, p. 6140 - 6143,4 (2020/09/16)
The gold(III)-catalyzed rearrangement of tetrasubstituted 1-alkynyloxiranes is described. This transformation led to a different reaction outcome with respect to related substrates previously studied. Thus, tertiary α-alkynylketones or alkynols can be selectively obtained. Moreover, gold(III) proved capable to catalyze the rearrangement of simple epoxides. These results indicate that gold(III) complexes act as oxophilic Lewis acids rather than π-acids in these transformations.
A one-pot cross-pinacol coupling/rearrangement procedure
Scheffler, Ulf,Mahrwald, Rainer
, p. 1970 - 1975,6 (2012/12/12)
A new catalytic retro-pinacol/cross-pinacol reaction, followed by subsequent rearrangement or deoxygenation of the intermediately formed vicinal diols, is described. This operationally simple one-pot protocol allows isolation of geminal α,α-diphenyl ketones or 1,1-diphenyl alkenes with high yields and selectivities. Copyright
