3425-72-7Relevant articles and documents
Sonochemical acetylation reactions of tertiary alkyl halides
Jayasree,Rao, J. Madhusudana
, p. 1103 - 1107 (1996)
A simple method for the acetylation of tertiary alkyl halides is described. The reaction was carried out using zinc acetate in presence of a phase transfer catalyst in an ultrasonic bath.
To Rebound or...Rebound? Evidence for the "alternative Rebound" mechanism in Ca'H Oxidations by the systems nonheme Mn Complex/H2O2/carboxylic acid
Ottenbacher, Roman V.,Bryliakova, Anna A.,Shashkov, Mikhail V.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
, p. 5517 - 5524 (2021/05/31)
In this work, it has been shown that aliphatic Ca'H oxidations by bioinspired catalyst systems Mn aminopyridine complex/H2O2/carboxylic acid in acetonitrile afford predominantly a mixture of the corresponding alcohol and the ester. The alcohol/ester ratio is higher for catalysts bearing electron-donating groups at the aminopyridine core. Isotopic labeling studies witness that the oxygen atom of the alcohol originates from the H2O2molecule, while the ester oxygen comes exclusively from the acid. Oxidation of ethylbenzene in the presence of acetic acid affords enantiomerically enriched 1-phenylethanol and 1-phenyl acetate, with close enantioselectivities and the same sign of absolute chirality. Experimental data and density functional theory calculations provide evidence in favor of the rate-limiting benzylic H atom abstraction by the high-spin (S = 1) [LMnV(O)OAc]2+active species followed by competitive OH/OC(O)R rebound. This mechanism has been unprecedented for Ca'H oxidations catalyzed by bioinspired Mn complexes. The trends governing the alcohol/ester ratios have been rationalized in terms of steric properties of the catalyst, acid, and substrate. copy; 2021 American Chemical Society.
Manganese-mediated acetylation of alcohols, phenols, thiols, and amines utilizing acetic anhydride
Jain, Isha,Sharma, Ramandeep,Malik, Payal
supporting information, p. 2952 - 2960 (2019/09/13)
Manganese(II) chloride-catalyzed acetylation of alcohols, phenols thiols and amines with acetic anhydride is reported. This method is environment-friendly and economically viable as it involves inexpensive, relatively benign catalyst, mild reaction condition, and simple workup. Acetylation is performed under the solvent-free condition at ambient temperature and acetylated products obtained in good to excellent yields. Primary, secondary heterocyclic amines, and phenols with various functional groups are smoothly acetylated in good yields. This method exhibits exquisite chemoselectivity, the amino group is preferentially acetylated in the presence of a hydroxyl/thiol group.
Chromatography-Free Esterification Reactions Using a Bifunctional Polymer
Ma, Shuang,Toy, Patrick H.
supporting information, p. 1207 - 1210 (2016/05/10)
A linear polystyrene functionalized with both nucleophilic DMAP groups and sterically hindered tertiary amine groups was synthesized and used homogeneously in a range of esterification reactions between alcohols and various carboxylic acid derivatives. The polymer was highly effective in such reactions where the DMAP groups served as catalytic groups. The ester products of these reactions could be isolated in high purity and yield without the need for chromatographic purification, and the polymer could be recovered and reused numerous times with no apparent decrease in utility.
Pyridinium saccharinate salts as efficient recyclable acylation catalyst: A new bridge between heterogeneous and homogeneous catalysis
Lu, Norman,Chang, Wei-Hsuan,Wei, Rong-Jyun,Fang, Yung-Cheng,Han, Tu-Wen,Wang, Guo-Quan,Chang, Jia-Yaw,Wen, Yuh-Sheng,Liu, Ling-Kang
, p. 3468 - 3476 (2016/06/06)
It is important to find a way for separation of concerned chemicals from product mixture after reaction, in order to avoid spreading harmful chemicals to society. The homogeneous nature of DMAP-catalyzed acylation still suffers from the problems of catalyst separation and/or residual DMAP contamination. DMAP causes acute dermal toxicity, whereas the corresponding DMAP salt exhibits only slight irritation to the skin. Very recently, we found that the DMAP saccharinate salt is also great recyclable catalyst, whose acylation of alcohols has been successfully and effectively carried out 10 times without loss in activity. This report covers our comprehensive studies on using the pyridinium saccharinate salts as efficient recyclable acylation catalysts including 4-N,N-dimethylaminopyridinium saccharinate (A), 4-(1-pyrrolidinyl) pyridinium saccharinate (B), 2-N,N-dimethylaminopyridinium saccharinate (C), and pyridinium saccharinate (D). Their structure and reactivity have been studied. The salts A, C, and D contain very interesting seven-membered synthon showing multiple H-bonding interactions for pair of pyridinium cation and saccharinate anion in the solid state. The salt B exhibits H-bonding interaction of N(sac) ... H-N(py) in the solid state, instead of seven-membered synthon. The catalytic reactivity studies show that salts A and B are both very effective, with salt B even better in reactivity, and are both recyclable in the esterification of a variety of alcohols, under solvent-free and base-free conditions at room temperature.
Efficient O-Acylation of Alcohols and Phenol Using Cp2TiCl as a Reaction Promoter
Durán-Pe?a, María Jesús,Botubol-Ares, José Manuel,Hanson, James R.,Hernández-Galán, Rosario,Collado, Isidro G.
supporting information, p. 3584 - 3591 (2016/07/28)
A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
Mechanism of Selective C-H Hydroxylation Mediated by Manganese Aminopyridine Enzyme Models
Ottenbacher, Roman V.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
, p. 39 - 44 (2015/04/27)
The mechanism of selective oxidation of aliphatic C-H groups with H2O2 in the presence of aminopyridine Mn complexes, modeling the reactivities of natural oxygenases of the cytochrome P450 superfamily, has been examined. The oxygenation of C-H groups proceeds via hydrogen atom abstraction by the electrophilic metal site; the logarithm of C-H oxidation rates correlates linearly with bond dissociation energies for homolytic C-H bond cleavage. Hammett correlations and stereospecificity studies reflect the formation of a short-lived electron-deficient radical intermediate. Isotopic labeling studies confirm the incorporation of 18O from added H218O, thus providing so far lacking evidence for the oxomanganese(V)-mediated oxidation mechanism. (Figure Presented).
Ceria nanoparticles as an efficient catalyst for oxidation of benzylic CH bonds
Akhlaghinia, Batool,Ebrahimabadi, Hossein,Goharshadi, Elaheh K.,Samiee, Sara,Rezazadeh, Soodabeh
experimental part, p. 67 - 72 (2012/05/20)
Catalytic oxidation of benzylic CH bonds with potassium bromate to carbonyl compounds was studied in the presence of ceria nanoparticles (NPs). Aldehydes and ketones in high yields were obtained when the oxidation was conducted in water/1,4-dioxane/acetic acid (AcOH) by ratio 5/1/1 (v/v/v). Benzyl esters were also yielded as the main products from the oxidation of benzylic CH bonds with potassium bromate in the presence of ceria NPs in glacial acetic acid. In comparison with other methods reported in the literature, ceria NPs as an efficient catalyst in oxidation of benzylic CH bonds have advantageous such as selectivity, recyclability, high reaction rate, and high yield of product because of their large specific surface area to volume ratio.
RECYCLABLE CATALYSTS FOR ESTERIFICATION OR ACYLATION OF ALCOHOLS
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Page/Page column 4, (2012/07/28)
A compound is useful as a recyclable catalyst for esterification or acylation of alcohols and consists of saccharine and a compound comprising a pyridine moiety. In addition, also a method of preparing the compound and an ester synthesis method using the compound are introduced.
A salt made of 4-N,N-dimethylaminopyridine (DMAP) and saccharin as an efficient recyclable acylation catalyst: A new bridge between heterogeneous and homogeneous catalysis
Lu, Norman,Chang, Wei-Hsuan,Tu, Wen-Han,Li, Chieh-Keng
supporting information; experimental part, p. 7227 - 7229 (2011/09/12)
Here, we report insights into the new recyclable catalyst 1, (DMAP·saccharin). The DMAP·saccharin-catalysed acylation of alcohols has been successfully carried out more than 8 times. Only 1 mol% of catalyst 1 efficiently promotes acylation with almost equimolar amounts of acid anhydrides, under both base-free and solvent-free conditions.
