581-55-5Relevant articles and documents
Selective Synthesis of Acylated Cross-Benzoins from Acylals and Aldehydes via N-Heterocyclic Carbene Catalysis
Onodera, Kou,Suzuki, Yumiko,Takashima, Ryo
supporting information, p. 4197 - 4202 (2021/06/27)
The utility of acylals as building blocks for selective cross-benzoin synthesis was explored in this study. The synthesis of α-acetoxyketones (O-acyl cross-benzoins) was achieved via selective N-heterocyclic carbene-catalyzed cross-benzoin reactions using acylals as aldehyde equivalents. Thus, the combination of ortho-substituted phenyl acylals and aromatic/aliphatic aldehydes as coupling substrates using bicyclic triazolium salts as precatalysts and potassium carbonate as a base in THF at reflux temperature selectively yielded O-acyl cross-benzoins.
Application of poly(Vinylbenzyltrimethylammonium tribromide) resin as an efficient polymeric catalyst in the acetalization and diacetylation of benzaldehydes
Han, Bingbing,Hu, Junjun,Li, Xianwei,Zheng, Zubiao
supporting information, p. 287 - 293 (2021/04/28)
The applications of a new supported tribromide reagent (poly(vinylbenzyltrimethylammonium tribromide) resin) were reported. This supported tribromide resin was used as a catalyst in the acetalization and diacetylation of benzaldehydes under mild conditions with high efficiency. The effects of solvents, and amount of the supported tribromide resin on the reactions were investigated. Under the optimal conditions, most of acetal and 1,1-diacetates of benzaldehydes were selectively obtained in excellent yields.
Sustainable electrochemical decarboxylative acetoxylation of aminoacids in batch and continuous flow
K?ckinger, Manuel,Hanselmann, Paul,Roberge, Dominique M.,Geotti-Bianchini, Piero,Kappe, C. Oliver,Cantillo, David
supporting information, p. 2382 - 2390 (2021/04/12)
Introduction of acetoxy groups to organic molecules is important for the preparation of many active ingredients and synthetic intermediates. A commonly used and attractive strategy is the oxidative decarboxylation of aliphatic carboxylic acids, which entails the generation of a new C(sp3)-O bond. This reaction has been traditionally carried out using excess amounts of harmful lead(iv) acetate. A sustainable alternative to stoichiometric oxidants is the Hofer-Moest reaction, which relies on the 2-electron anodic oxidation of the carboxylic acid. However, examples showing electrochemical acetoxylation of amino acids are scarce. Herein we present a general and scalable procedure for the anodic decarboxylative acetoxylation of amino acids in batch and continuous flow mode. The procedure has been applied to the derivatization of several natural and synthetic amino acids, including key intermediates for the synthesis of active pharmaceutical ingredients. Good to excellent yields were obtained in all cases. Transfer of the process from batch to a continuous flow cell signficantly increased the reaction throughput and space-time yield, with excellent product yields obtained even in a single-pass. The sustainability of the electrochemical protocol has been examined by evaluating its green metrics. Comparison with the conventional method demonstrates that an electrochemical approach has a significant positive effect on the greenness of the process.
The studies on chemoselective promiscuous activity of hydrolases on acylals transformations
Koszelewski, Dominik,Ostaszewski, Ryszard
, (2019/02/27)
Chemoselective, mild and convenient protocol for the hydrolysis of the synthetically relevant acylals via promiscuous enzyme-catalyzed hydrolysis has been developed. It has been shown that promiscuous activity of the used hydrolases dominates their native activity related with carboxylic esters hydrolysis. The main advantage of the present methodology is that it can be conducted under neutral conditions at room temperature. Moreover, complete deprotection of acylals takes place within 10–20 min. Developed protocol can be used with compounds having a variety of hydrolytic labile groups since the cleavage is proceeded under neutral conditions and occurs exclusively on acylal moiety. Further this protocol was extended by the tandem Passerini multicomponent reaction leading to the α-acetoxy amides using acylals as the surrogates of the carbonyl components to P-MCR.
Acylation of Phenols, Alcohols, Thiols, Amines and Aldehydes Using Sulfonic Acid Functionalized Hyper-Cross-Linked Poly(2-naphthol) as a Solid Acid Catalyst
Kalla, Reddi Mohan Naidu,Reddy, Sirigireddy Sudharsan,Kim, Il
, p. 2696 - 2705 (2019/05/28)
Abstract: The hyper-cross-linked porous poly(2-naphthol) fabricated by the Friedel–Crafts alkylation of 2-naphthol has been functionalized with sulfonic acid to obtain a solid acid catalyst. The catalyst is applied for the protection of phenol, alcohols, thiols, amines and aldehydes with acetic anhydride at room temperature. The catalytic protection using the new solid acid is featured by achieving high yield at neat condition, needing no aqueous work-up and/or chromatographic separation, and showing excellent recycling efficiency, suggesting the potential of this sulfonated porous polymers as a new protection protocol in a wide range of sustainable chemical reactions. Graphical Abstract: [Figure not available: see fulltext.].
1,1-Diacyloxy-1-phenylmethanes as versatile N-acylating agents for amines
Chapman, Robert. S.L.,Tibbetts, Joshua. D.,Bull, Steven. D.
, p. 5330 - 5339 (2018/06/15)
1,1-Diacyloxy-1-phenylmethanes and 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as bench stable N-acylating reagents for primary and secondary amines and anilines under solvent-free conditions to afford their corresponding amides in good yield.
N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) as a green and reusable heterogeneous nanocatalyst for the chemoselective preparation and deprotection of acylals
Sajjadifar, Sami,Nasri, Parastoo
, p. 6677 - 6689 (2017/10/06)
Abstract: N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was simply synthesized and used as a highly efficient, environmentally friendly, and chemoselective catalyst for the synthesis of 1,1-diacetates (acylals) from the one-pot condensation reaction of various aromatic aldehydes with acetic anhydride, in high yield of products (86–96%) and short reaction time (20–60?min) under solvent-free conditions at room temperature. In addition to these results, we further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water. More importantly, noteworthy advantages of this study are non-use of toxic organic solvents and catalysts, simple work-up procedure, short reaction time, high yield of products, and recovery and reusability of MNPs-PSA by an external magnet. Graphical Abstract: A simple and highly efficient procedure for the protection of various aldehydes with acetic anhydride in the presence of N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) is reported. We further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water as a green solvent. The catalyst was reused several times without loss of its catalytic activity.
SiO2@FeSO4 nano composite as nanocatalyst for the green synthesis 1,1-diacetates from aldehydes under solvent-free conditions
KarimKoshteh, Mostafa,Bagheri, Marziyeh,Zeynizadeh, Behzad
, p. 2780 - 2783 (2016/07/12)
Aldehydes compounds selective converted to 1,1-diacetates as protective reagent with SiO2@FeSO4 nano composite as effective nano catalyst at room temperature under solvent-free condition and acetic anhydride (Ac2O) as acet
Microwave-assisted green synthesis of 1,1-diacetates (acylals) using selectfluor as an environmental-friendly catalyst under solvent-free conditions
Rezayati, Sobhan,Hajinasiri, Rahimeh,Erfani, Zahra
, p. 2567 - 2576 (2016/03/16)
An efficient and simple procedure has been developed for the acetylation of aldehyde by selectfluor [1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2,2,2]octane bis(tetrafluoroborate)] as a chemoselective and environmentally friendly catalyst under solvent-free conditions or microwave irradiation. The application of microwave irradiation improved the yields and reduced the reaction times. In this study, selective conversion of aldehydes was observed in the presence of ketones, and the deprotection of 1,1-diacetates has also been achieved using selectfluor in water as green solvent in reflux conditions. The methodology provides synergy of microwave irradiation which offers several advantages such the simple work-up procedure, short reaction time, excellent yields and environmentally benign procedure.
Tungstosulfonic acid as an efficient solid acid catalyst for acylal synthesis for the protection of the aldehydic carbonyl group
Kalla, Reddi Mohan Naidu,Kim, Mi Ri,Kim, Yu Na,Kim, Il
supporting information, p. 687 - 693 (2016/01/12)
Tungstosulfonic acid (TSA) has been found to be an efficient solid acid catalyst for the protection of aldehydic carbonyl groups by geminal diacetate (acylal) formation following the nucleophilic addition of acetic anhydride under neat conditions as well as in a solvent. The TSA catalyst is fully characterized by infrared spectroscopy, wide-angle X-ray scattering analysis, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The deprotection of acylals to corresponding aldehydes has also been investigated under the similar conditions. The catalyst can be reused seven times without a significant loss of activity. In addition, no chromatographic separations are needed to obtain the desired products. This method is a green approach for the chemoselective protection of aldehydes in the presence of ketones.
