62-23-7Relevant articles and documents
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Wardner,Lowy
, p. 2510,2514 (1932)
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Studies on a dithiane-protected benzoin photolabile safety catch linker for solid-phase synthesis
Hong Boon Lee,Balasubramanian
, p. 3454 - 3460 (1999)
Substituted benzoinyl systems 8a-g, differing either in the substitution pattern, type of resin matrix used, or resin loading capacity, were prepared and the kinetics of their photolytic cleavage of Fmoc-β-alanine examined on resin. The linker systems 6a-g were assembled in near-quantitative yield using Corey-Seebach dithiane addition. The dithiane group that serves as a safety catch against premature photoreaction was removed by either oxidation or alkylation. Analytical methods that include FTIR and 13C gel-phase NMR spectroscopy were used for rapid reaction monitoring and sample characterization on resin. A survey of different substituted systems 8c-f for releasing Fmoc-β-alanine confirmed that the 3-alkoxybenzoin linker photocleaves most rapidly to give the highest yield (τ(1/2) = 6.7 min; 98% yield). Lowering the resin loading from 0.59 mmol/g in 8a to 0.26 mmol/g in 8b improved the cleavage kinetics to τ(1/2) = 2.6 min, 92% yield. Tentagel resin 8g exhibits similar photocleavage kinetics in both organic and aqueous media and when compared to the polystyrene counterpart, 8a. The 3- alkoxybenzoin linker 6a was also loaded with aryl carboxylic acids (12h,i) and hindered Fmoc-protected amino acids (12j-l) with varying degrees of success (57-100%) and dithiane deprotected (70-80%, 13h-1) followed by photocleavage with comparable efficiencies (8993% after 60 min).
Disproportionation of 4-Nitroacetophenone to 4-Aminoacetophenone and 4-Nitrobenzoic Acid
Wan, Peter,Xu, Xigen
, p. 4473 - 4474 (1989)
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2-(5-Arylterphenyl-4-yl)quinolines from 2-methylquinoline and 1-(het)aryl-3-phenylprop-2-yn-1-ones in just a one step: A miracle of molecular interplay
Trofimov, Boris A.,Belyaeva, Kseniya V.,Nikitina, Lina P.,Afonin, Andrei V.,Vashchenko, Alexander V.
, p. 267 - 269 (2018)
2-Methylquinoline reacts with 1-(het)aryl-3-phenylprop-2-yn-1-ones under mild transition metal-free conditions (55–60 °C, 20 mol% KOH, H2O, MeCN) to afford 2-{5’-(het)aryl[1,1’: 3’,1”]terphenyl-4’-yl}quinolines in up to 35% yield. The reaction likely proceeds via the intermediate 1,3-dipole followed by the double nucleophilic vinylation of the methyl group with two molecules of ynone and subsequent elimination of (het)arenecarboxylic acid.
Hey
, p. 2636,2638 (1932)
Use of ozone for preparing 4-nitrobenzoic acid in a closed process cycle
Galstyan,Tyupalo,Patapenko,Andreev
, p. 1777 - 1779 (2001)
The possibility of preparing 4-nitrobenzoic acid in a closed process cycle by oxidation of 4-nitrotoluene with an ozone air mixture was examined. The optimal conditions of oxidation with multiple use of mother liquors were found, and the conditions for crystallization of 4-nitrobenzoic acid from the reaction mixture were determined. The effects of water, acetic anhydride, and catalyst on the oxidation performed in mother liquors after filtration of the target product were examined.
Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
, p. 803 - 808 (2021/07/20)
Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
Practical scale up synthesis of carboxylic acids and their bioisosteres 5-substituted-1H-tetrazoles catalyzed by a graphene oxide-based solid acid carbocatalyst
Mittal, Rupali,Kumar, Amit,Awasthi, Satish Kumar
, p. 11166 - 11176 (2021/03/31)
Herein, catalytic application of a metal-free sulfonic acid functionalized reduced graphene oxide (SA-rGO) material is reported for the synthesis of both carboxylic acids and their bioisosteres, 5-substituted-1H-tetrazoles. SA-rGO as a catalytic material incorporates the intriguing properties of graphene oxide material with additional benefits of highly acidic sites due to sulfonic acid groups. The oxidation of aldehydes to carboxylic acids could be efficiently achieved using H2O2as a green oxidant with high TOF values (9.06-9.89 h?1). The 5-substituted-1H-tetrazoles could also be effectively synthesized with high TOF values (12.08-16.96 h?1). The synthesis of 5-substituted-1H-tetrazoles was corroborated by single crystal X-ray analysis and computational calculations of the proposed reaction mechanism which correlated well with experimental findings. Both of the reactions could be performed efficiently at gram scale (10 g) using the SA-rGO catalyst. SA-rGO displays eminent reusability up to eight runs without significant decrease in its productivity. Thus, these features make SA-rGO riveting from an industrial perspective.