F:Flammable;
75-97-8Relevant articles and documents
Ionic crystals [M3O(OOCC6H5) 6(H2O)3]4[α-SiW 12O40] (M = Cr, Fe) as heterogeneous catalysts for pinacol rearrangement
Uchida, Sayaka,Lesbani, Aldes,Ogasawara, Yoshiyuki,Mizuno, Noritaka
, p. 775 - 777 (2012)
Complexation of trinuclear oxo-centered carboxylates with a silicododecatungstate resulted in the formation of ionic crystals of [M 3O(OOCC6H5)6(H2O) 3]4[α-SiW12O40]·nH 2O·mCH3COCH3 [M = Cr (Ia), Fe (IIa)]. Treatments of Ia and IIa at 373 K in vacuo formed guest-free phases Ib and IIb, respectively. Compounds Ib and IIb heterogeneously catalyzed the pinacol rearrangement to pinacolone with high conversion at 373 K, and the catalysis is suggested to proceed size selectively in the solid bulk.
The role of SET in the deprotection of (thio)ketals under photosensitization by π-acceptors
Fasani, Elisa,Freccero, Mauro,Mella, Mariella,Albini, Angelo
, p. 2219 - 2232 (1997)
Efficient deprotection of 2-methyl-2-tert-butyl-1,3-dithiolane and of the corresponding oxathiolane to give the ketone is obtained by photosensitization by a catalytic amount of aromatic nitriles (benzenetetracarbonitrile, TCB, and antracenedicarbonitrile, DCA the latter only in the presence of biphenyl) or of heterocyclic salts (triphenylpyrylium tetrafluoborate, TPPT, and methylacridinium perchlorate, MAP), in oxygen saturated solutions. The reaction involves SET to the excited π-acceptor and interception of the substrate radical cation either by oxygen (in the case of the heterocyclics) or by the superoxide anion (in the case of the nitriles). Triplet chloranil (Chl) acts both as oxidant and as proton acceptor, and thus deprotection is accompanied by formation of a stoichiometric amount of the hydroquinone ChlH2. The corresponding dioxolane is a weaker donor: SET occurs only with photoexcited TCB and causes C-C bond fragmentation, not deprotection. The other π-acceptors photosensitize the deprotection of the dioxolane, but in this case they act as Lewis acids (Chl gives a trimer under this condition). This method is unsatisfactory with protected aldehydes. The different reactivity of the radical cations of thioketals and of ketals and the scope of this deprotection method are discussed.
Acceleration of synthetic organic reactions using supercritical water: Noncatalytic Beckmann and pinacol rearrangements
Ikushima, Yutaka,Hatakeda, Kiyotaka,Sato, Osamu,Yokoyama, Toshirou,Arai, Masahiko
, p. 1908 - 1918 (2000)
A high-pressure and high-temperature FTIR was used to study noncatalytic Beckmann and pinacol rearrangements using supercritical water (scH2O). Significant acceleration of Beckmann and pinacol rearrangements can be achieved by using scH2O, especially near the critical point, even in the absence of any acid catalysts. It has been demonstrated that scH2O acts effectively in the place of conventional acid catalysts for both the rearrangements. The rate of pinacol rearrangement using scH2O is significantly larger by a factor of 28200 than that in 0.871 M HCl solution at 46.7 MPa under distillation conditions. The activation energy for the former at 25 MPa was found to be markedly reduced to about one-third of that for the latter. The accelerated rates of reaction may be attributed to a great increase in the local proton concentration around the organic reactants. In addition, the nature of scH2O can be adjustable to weak acidity in the near-critical region, and then it does not catalyze the pinacol rearrangement, but opens a new reaction pathway from pinacol through a completely dehydrated product and then to a Diels-Alder adduct between the dehydrated products.
Isomeric effects on the acidity of Al13Keggin clusters in porous ionic crystals
Ogiwara, Naoki,Tamai, Nanako,Uchida, Sayaka,Weng, Zhewei,Yan, Li-Kai,Zhao, Congcong,Zhou, Wei
supporting information, p. 8893 - 8896 (2021/09/10)
We demonstrate a facile synthesis method of a porous ionic crystal (PIC) composed of the little-known δ-Keggin-type cationic polyoxoaluminum cluster ([δ-Al13O4(OH)24(H2O)12]7+, δ-Al13) with an oppositely-charged polyoxometalate, which enabled us to investigate the activity as a solid acid. The δ-Al13based PIC exhibited much higher activity in pinacol rearrangement, a typical acid-catalyzed reaction, than the PIC based on the well-known and thermodynamically stable rotational isomer (ε-Al13). This work is a rare example of rotational isomers of polyoxoaluminum clusters exhibiting remarkably different catalytic activities.
Catalytic Acceptorless Dehydrogenation of Aliphatic Alcohols
Fuse, Hiromu,Mitsunuma, Harunobu,Kanai, Motomu
supporting information, p. 4493 - 4499 (2020/03/05)
We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centered radical with a nickel catalyst, and β-hydride elimination. The reaction proceeded in high yield under mild conditions without producing side products (except H2 gas) from various alcohols, including sterically hindered alcohols, a steroid, and a pharmaceutical derivative. This catalyst system also promoted acceptorless cross-dehydrogenative esterification from aldehydes and alcohols through hemiacetal intermediates.
Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation
Ye, Danfeng,Liu, Zhiyuan,Sessler, Jonathan L.,Lei, Chuanhu
supporting information, p. 11811 - 11814 (2020/10/13)
An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstratedviathe facile oxidation of structurally complicated natural products.
Production process of dichloro pinacolone (by machine translation)
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Paragraph 0011, (2020/12/29)
The production process is characterized in that the specific production process is as follows: S1: 2 - Chloropentane preparation. S2: pinacolone. S3: pinacolone rectification. S4: synthesis of dichloro-pinacolone. S5: treatment of by-products. In addition, by adopting formaldehyde addition in the chlorination reaction, the reaction rate 3 times or more can be inhibited, and reaction and cooling can be completed between a general reaction requirement 70 - 75 hours by adding formaldehyde, and cooling by adopting chilled water, so that the production efficiency is greatly improved 20 - 25 hours. (by machine translation)
Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
supporting information, p. 8143 - 8146 (2020/09/09)
The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
Transfer-dehydrogenation of secondary alcohols catalyzed by manganese NNN-pincer complexes
Budweg, Svenja,Junge, Kathrin,Beller, Matthias
supporting information, p. 14143 - 14146 (2019/12/02)
Novel catalytic systems based on pentacarbonylmanganese bromide and stable NNN-pincer ligands are presented for the transfer-dehydrogenation of secondary alcohols to give the corresponding ketones in good to excellent isolated yields. Best results are obtained using di-picolylamine derivatives as ligands and acetone as an inexpensive hydrogen acceptor. Besides high activity for benzylic substrates, aliphatic alcohols, as well as steroid derivatives, are readily oxidized in the presence of the optimal phosphorus-free catalyst.
Synthesis method of primary amine hydrochloride
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Paragraph 0124-0127, (2019/03/09)
The invention discloses a synthesis method of primary amine hydrochloride. According to the synthesis method, in the presence of a gold complex, water and alkyne carry out catalytic hydrolysis to generate ketones, and then ketones and ammonium formate are catalyzed by a rhodium complex to generate primary amine. Compared with a conventional primary amine synthesis method, the synthesis method hasthe advantages that no alkali is added during the reaction process, no side product is generated, the atomic economy is good, the reaction conditions are mild, and the synthesis method has a wide prospect.
