112-14-1Relevant articles and documents
Diversification of shotgun process
Nagano, Yoshifumi,Orita, Akihiro,Otera, Junzo
, p. 5569 - 5578 (2003)
Three protocols for shotgun process are put forth in which simultaneous multi-fold reactions occur exclusively to each other. The first one involves simple combination of selective and non-selective reactions. Even if the simple protocol fails to give rise to the high selectivity, satisfactory outcome can be achieved by kinetic control or adjustment of functional groups.
Organotin catalysts rafted onto cross-linked polystyrene supports through polar spacers
Pinoie, Vanja,Biesemans, Monique,Willem, Rudolph
, p. 135 - 141 (2010)
The present study investigates the suitability of a HypoGel support bearing oligomeric poly(ethylene glycol) (PEG) chains to act as an insoluble carrier for grafted organotin catalysts. Through the introduction of polar spacers, an improved swelling and site accessibility in the polar media typically involved in transesterification reactions are targeted. Advanced structural investigation shows that quantitative conversion into the targeted HypoGel-supported organotin trichloride is hampered by the existence of intra-and/or intermolecular donor-acceptor O → Sn interactions caused by the presence of donor moieties in the PEG-linker. Support is provided to the proposal that the latter interactions are at the origin of the moderate catalytic performance displayed by these HypoGel-supported catalysts, achieving only 41% conversion after 2 hours in the transesterification of ethyl acetate and n-octanol. In contrast with similar organotin catalysts supported by an alkyl spacer, the HypoGel-supported materials appear to be poorly recyclable and display poor leaching resistance. Copyright
Alkylation of potassium acetate in "dry media" thermal activation in commercial microwave ovens
Bram, Georges,Loupy, Andre,Majdoub, Mustapha,Gutierrez, Elvira,Ruiz-Hitzsky, Eduardo
, p. 5167 - 5176 (1990)
Microwave irradiation using commercial domestic ovens is very efficient to activate potassium acetate on alumina in the absence of solvent ("dry media") giving rise to remarkable rate enhancements in alkylation reactions with long chain halides. These reactions can be performed quantitatively on appreciable amounts of materials in open standard pyrex vessels.
A powerful tool for acid catalyzed organic addition and substitution reactions
Turhanen, Petri A.,Veps?l?inen, Jouko J.
, p. 26218 - 26222 (2015)
A novel green chemistry tool for acid catalyzed reactions has been developed. The multipurpose tool is based on the ability of dry solid materials to donate protons (H+) to starting materials combined with the simultaneous use of a nucleophile (e.g. NaI). The methods enable the following reactions to be conducted at 20-50 °C: selective addition of iodine or alcohols to more substituted carbon in R2CCH2 systems (R ≠ H), esterification reactions, e.g. free fatty acids with methanol, and at higher temperatures, (60-100 °C): esterification of free fatty acids with hindered alcohols (isopropanol), addition of iodine to CC bonds, opening of oxygen(s) containing heterocyclic rings, selective substitution of primary OH groups to iodine in the presence of other functional groups or secondary alcohol groups, esterification of alcohols with nitriles (R-CN), transesterification of fatty acid triglycerides to biodiesel and selective derivatization of primary hydroxyl groups (-CH2OH) over secondary moieties of sugars without any protection. Most of the reactions were also performed by a re-used Dowex cation exchange resin.
Erbium(III) triflate as an extremely active acylation catalyst
Procopio, Antonio,Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Russo, Beatrice,Sindona, Giovanni
, p. 1465 - 1470 (2004)
Erbium(III) triflate is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides {Ac 2O, (EtCO)2O, [(CH3)3CO] 2O, Bz2O, and (CF3CO)2O} without isomerisation of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.
INORGANIC SOLIDS IN "DRY MEDIA" AN EFFICIENT WAY FOR DEVELOPING MICROWAVE IRRADIATION ACTIVATED ORGANIC REACTIONS
Gutierrez, E.,Loupy, A.,Bram, G.,Ruiz-Hitzky, E.
, p. 945 - 948 (1989)
"Dry media" microwave irradiation accelerates pinacol rearrangement (on montmorillonite) or acetate alkylation (on alumina or silicagel) without the hazards due to high pressures in vessels when using solvents.
A new Br?nsted acid MIL-101(Cr) catalyst by tandem post-functionalization; synthesis and its catalytic application
Mortazavi, Saeideh-Sadat,Abbasi, Alireza,Masteri-Farahani, Majid
, (2020)
A new heterogeneous Br?nsted solid acid catalyst was prepared by tandem post-functionalization of MIL-101(Cr) and utilized for acetic acid esterification and alcoholysis of epoxides under solvent-free conditions. First, MIL-101(Cr) was functionalized with pyrazine to achieve MIL-101(Cr)-Pyz. Afterwards, the nucleophilic reaction of MIL-101(Cr)-Pyz with 1,3-propane sultone and next acidification with diluted sulfuric acid gave MIL-101(Cr)-Pyz-RSO3H Br?nsted solid acid catalyst. Various characterization methods such as Fourier transformation infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), elemental analysis (CHNS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersiveX-ray(EDX) spectroscopy, thermal analysis (TGA/DTA), acid–base titration, and N2 adsorption/desorption analysis were employed to fully characterize the prepared catalyst. The catalyst showed high activity compared to unmodified MIL-101(Cr) in both catalytic acetic acid esterification and alcoholysis of epoxides. It can also be readily isolated from the reaction mixture and reused three times without major decrease in its activity.
A carbonyl oxide route to antimalarial Yingzhaosu A analogues: Synthesis and antimalarial activity
O'Neill, Paul M.,Searle, Natalie L.,Raynes, Kaylene J.,Maggs, James L.,Ward, Stephen A.,Storr, Richard C.,Park, B.Kevin,Posner, Gary H.
, p. 6065 - 6068 (1998)
Ozonolysis of R-carvone and in situ trapping with primary alcohols ROH (R = Me, Et, Bu, Pent, Oct) produces hydroperoxy ketals (5a-e) as a 1:1 mixture of diastereomers. Cyclisation of these intermediates with catalytic sodium methoxide in methanol produces the corresponding endoperoxide derivatives (6a-6e). The pentyl and octyl endoperoxide derivatives demonstrate reasonable antimalarial potency in vitro against the HB3 strain of Plasmodium falciparum. A mechanism for antimalarial action involving the formation of a C-centred radical is proposed.
Masuda,Arase
, p. 901 (1978)
A novel 3-nitrobenzeneboronic acid as an extremely mild and environmentally benign catalyst for the acetylation of alcohols under solvent-free conditions
Tale,Adude
, p. 7263 - 7265 (2006)
A novel 3-nitrobenzeneboronic acid is found to catalyse efficiently the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields at room temperature under solvent-free conditions. The reactions are clean and the catalyst is mild such that highly sensitive functional groups including oximes are stable to the reaction conditions.
Selective acylation of aliphatic alcohols in the presence of phenolic hydroxyl groups
Sabitha, Gowravaram,Subba Reddy, Basi V.,Kiran Kumar Reddy, Garudammagari S.,Yadav, Jhillu S.
, p. 63 - 64 (2000)
A new and efficient method for the selective acylation of aliphatic hydroxyl groups in the presence of phenolic groups using a mixture of trimethyl orthoacetate and trimethylsilyl chloride at room temperature is reported. The reactions are selective, high yielding and complete within 3-6 h.
Scope and limitations of the use of grafted undecyltin trichloride as a catalyst for transesterifications: Effect of tin loading on catalytic activity, recyclability, and leaching
Pinoie, Vanja,Biesemans, Monique,Willem, Rudolph
, p. 193 - 198 (2010)
The effect of the tin loading (functionalization degree t) on the catalytic activity and recyclability is investigated for a polystyrene-grafted undecyltin trichloride catalyst, P-C11-SnCl3, in transesterification reactions involving either a primary or a secondary alcohol. For the latter, the achieved conversion degree in the first run is about 20% lower than with the primary alcohol. In subsequent runs, the reaction rates are strongly influenced by the tin loading of the catalyst. Unlike low-loaded P-C11-SnCl3 catalysts (t ≈ 0.10), high-loaded catalysts (t ≈ 0.20) display a simultaneous T g increase (from 53 °C to 107 °C after 5 runs) and conversion decrease (from 52% to 15%) upon increasing number of runs, ascribed to reduced mobility of the organotin moieties resulting from undesired cross-linking at the reaction interface. Confirmation for the fact that, in this case, the catalytic performance is dominated by conformational mobility issues is found in the comparison between transesteriflcations involving either primary or secondary alcohols. Whereas a Tg increase is not associated with a reduced conversion degree for primary alcohols, a clear decrease in conversion is observed for secondary alcohols, illustrating that steric issues are especially pronounced in a low-mobility (high-loaded) system and are of no importance in high-mobility (low-loaded) systems. This also affects the leaching resistance of the compounds, the high-loaded catalysts displaying substantially higher tin leaching (311 ± 278 ppm) than the low-loaded ones (10 ± 8 ppm).
A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
, p. 3404 - 3408 (2021/07/14)
The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
Second-Generation meta-Phenolsulfonic Acid-Formaldehyde Resin as a Catalyst for Continuous-Flow Esterification
Hu, Hao,Ota, Hajime,Baek, Heeyoel,Shinohara, Kenta,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
supporting information, p. 160 - 163 (2020/01/02)
A second-generation m-phenolsulfonic acid-formaldehyde resin (PAFR II) catalyst was prepared by condensation polymerization of sodium m-phenolsulfonate and paraformaldehyde in an aqueous H2SO4 solution. This reusable, robust acid resin catalyst was improved in both catalytic activity and stability, maintaining the characteristics of the previous generation catalyst (p-phenolsulfonic acid-formaldehyde resin). PAFR II was applied in the batchwise and continuous-flow direct esterification without water removal and provided higher product yields in continuous-flow esterification than any other commercial ion-exchanged acid catalyst tested.
