1670-47-9Relevant academic research and scientific papers
A highly efficient and chemoselective method for acetalization of carbonyl compounds catalyzed by TiO2/SO42- solid superacid
Ma, Yan-Ran,Jin, Tong-Shou,Shi, Sheng-Xun,Li, Tong-Shuang
, p. 2103 - 2108 (2003)
Various types of aldehydes and ketones could be converted to their corresponding diethyl acetals with triethylorthoformate in the presence of TiO2/SO42- solid superacid in good to excellent yield under mild reaction conditions.
Catalysis of a peptidic micellar assembly covalently immobilized within mesoporous silica channels: Importance of amphiphilic spatial design
Otani, Wataru,Kinbara, Kazushi,Zhang, Qingmin,Ariga, Katsuhiko,Aida, Takuzo
, p. 1731 - 1736 (2007)
A mesostructured silica/organic composite 1-MS, constructed from a rodlike micelle of amino acid amphiphile 1 that has a condensable head group and that can be used as a template, was found to be able to catalyze the acetalization of cyclohexanone, in ethanol at 25 °C (50% in 12 h), whereas no reaction took place with unfunctionalized mesoporous silica. In sharp contrast, hydrolytic removal of the C16 alkyl tail of immobilized 1 resulted in the complete disappearance of the catalytic activity, which suggests the importance of a Hydrophobic inner domain for the admission of cyclohexanone. Unsupported peptide amphiphile 2, under identical conditions to those above, was inefficient for acetalization regardless of the absence (2% in 24 h) or presence of mesoporous silica (7% in 24 h). Reference composite 2-MS, which is a noncovalently immobilized peptidic micelle, was virtually inactive (1 % in 24 h). These observations indicate the importance of covalent immobilization of the peptidic rod micelle for catalysis. Mesostructured silicate 3MS hybridized with a nonpeptidic, ammonium ion amphiphile (3) showed a certain catalytic activity, but the yield (12% in 24 h) of the acetal was much lower than that achieved by using 1MS as the catalyst. Amorphous silica with immobilized 1 on its surface was much less active than 1-MS for acetalization (5% in 24 h).
Practical acetalization and transacetalization of carbonyl compounds catalyzed by recyclable PVP-I
Cao, Fu-Rong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
, (2021/06/21)
A novel PVP-I catalyzed acetalizations/transacetalizations of carbonyl compounds has been developed processing with a mild and easy handling fashion. Different types of Acyclic and cyclic acetals were prepared from carbonyl compounds or their acetals successfully. Further applications of newly developed catalytic combination were testified. This protocol featured with simplicity of operation, mild reaction condition, short reaction time, recyclable of catalyst and broad substrates scope with excellent yields.
A novel, mesoporous molybdenum doped titanium dioxide/reduced graphene oxide composite as a green, highly efficient solid acid catalyst for acetalization
He, Junkai,Kankanam Kapuge, Tharindu,Kerns, Peter,Meguerdichian, Andrew G.,Suib, Steven L.,Thalgaspitiya, Wimalika R. K.
, p. 3786 - 3795 (2020/04/03)
A novel, mesoporous composite of Mo doped TiO2/reduced graphene oxide is synthesized to be used as a highly efficient heterogeneous acid catalyst. The composite has a high surface area (263 m2 g-1) and a monomodal pore size distribution with an average pore diameter of 3.4 nm. A comprehensive characterization of the synthesized material was done using PXRD, Raman, BET, SEM, EDX, TEM, TGA, and XPS. The composite exhibited excellent catalytic activity (1.6 h-1 TOF, >99% GC yield, and >99% selectivity) towards acetalization of cyclohexanone at room tempertaure within 30 minutes. The catalyst was reusable up to 4 reaction cycles without any significant loss in the activity and the acidic site calculations showed that the reaction is mostly driven by the weak acidic sites on the composite.
Mechanistic Studies on the Base-Promoted Conversion of Alkoxy-Substituted, Ring-Fused gem-Dihalocyclopropanes into Furans: Evidence for a Process Involving Electrocyclic Ring Closure of a Carbonyl Ylide Intermediate
Sharp, Phillip P.,Mikusek, Jiri,Ho, Junming,Krenske, Elizabeth H.,Banwell, Martin G.,Coote, Michelle L.,Ward, Jas S.,Willis, Anthony C.
, p. 13678 - 13690 (2018/11/10)
The mechanism associated with the base-promoted conversion of alkoxy-substituted and ring-fused gem-dihalocyclopropanes such as 40 into annulated furans has been explored. Treatment of compound 40 with potassium tert-butoxide affords a mixture of furans 23/27 and 41, an outcome that suggests the intermediacy of the slowly interconverting carbonyl ylides 42 and 43 that undergo rapid [1,5]-electrocyclizations and subsequent dehydrohalogenation to afford the observed products. This proposal is supported by ab initio MO and DFT calculations that also suggest a vinylcarbene insertion pathway is less likely to be operative.
Method for catalytic synthesis of cyclohexanone ethylene ketal from titanium phosphotungstate and ammonium phosphotungstate composite salt
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Paragraph 0021-0031, (2018/07/30)
The invention relates to a method for catalytic synthesis of cyclohexanone ethylene ketal from titanium phosphotungstate and ammonium phosphotungstate composite salt. The titanium phosphotungstate andammonium phosphotungstate composite salt is taken as a catalyst, cyclohexanone ethylene ketal is generated from cyclohexanone and ethylene glycol through a condensation reaction, and the condensed structural formula of the titanium phosphotungstate and ammonium phosphotungstate composite salt is (NH4)xTiyH(3-x-4y)PW12O40, wherein x=0.4-0.6, and y=0.4-0.6. The titanium phosphotungstate and ammonium phosphotungstate composite salt as the catalyst has larger specific surface area, higher surface acid density and proper acid strength, so that the catalyst has excellent catalytic performance, andproduct yield is high. Besides, raw materials of the catalyst are easily available, the preparation process is simple, the catalyst and the product are easy to separate, and the catalyst is recyclable.
A Lamellar Coordination Polymer with Remarkable Catalytic Activity
Mendes, Ricardo F.,Antunes, Margarida M.,Silva, Patrícia,Barbosa, Paula,Figueiredo, Filipe,Linden, Anthony,Rocha, Jo?o,Valente, Anabela A.,Almeida Paz, Filipe A.
, p. 13136 - 13146 (2016/09/09)
A positively charged lamellar coordination polymer based on a flexible triphosphonic acid linker is reported. [Gd(H4nmp)(H2O)2]Cl?2 H2O (1) [H6nmp=nitrilotris(methylenephosphonic acid)] was obtained by a one-pot approach by using water as a green solvent and by forcing the inclusion of additional acid sites by employing HCl in the synthesis. Compound 1 acts as a versatile heterogeneous acid catalyst with outstanding activity in organic reactions such as alcoholysis of styrene oxide, acetalization of benzaldehyde and cyclohexanaldehyde and ketalization of cyclohexanone. For all reaction systems, very high conversions were reached (92–97 %) in only 15–30 min under mild conditions (35 °C, atmospheric pressure). The coordination polymer exhibits a protonic conductivity of 1.23×10?5S cm?1at 98 % relative humidity and 40 °C.
Mixed (Fe2+ and Cu2+) double metal hexacyanocobaltates as solid catalyst for the aerobic oxidation of oximes to carbonyl compounds
Garcia-Ortiz, Alma,Grirrane, Abdessamad,Reguera, Edilso,Garcia, Hermenegildo
, p. 386 - 392 (2014/02/14)
Mixed Iron and copper hexacyanocolbatate was found to be a suitable heterogeneous and recoverable catalyst for the aerobic oxidation of oximes to the corresponding ketone. The reaction can be conveniently carried out in water-ethanol 1-1 mixture as solvent. The tinme-conversion plots shows the presence of an induction period that do not correspond to the leaching of metal ions or to the damage of the crystal structure of the material. The proposed reaction mechanism is based on the cooperation of the Lewis acidity of iron with the ability of copper to interact with oxygen. Given the remarkable stability of metal hexacyanocobaltates and the large diversity of metals that can contain, our reports opens the way for the general use of these affordable and accessible solids as heterogeneous catalysts.
Zeolite nanofiber assemblies as acid catalysts with high activity for the acetalization of carbonyl compounds with alcohols
Liu, Taotao,Fu, Wenqian,Zheng, Xiang,Jiang, Jun,Hu, Maolin,Tang, Tiandi
, p. 18217 - 18221 (2014/05/20)
Zeolite nanofiber assemblies (HNB-MOR) as efficient heterogeneous catalysts for the formation of a range of acetals in good yields. The mesoporosity of HNB-MOR benefits mass transfer, and the strong acidic sites on HNB-MOR facilitate acetalization activity. The catalyst can be reused 10 times without loss of activity.
PROCESS FOR THE PREPARATION OF RAPAMYCIN DERIVATIVES
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Page/Page column 13, (2012/08/27)
The invention relates to processes for the preparation of compound of CCI-779 having the Formula (I), which is useful as an antineoplastic agent. The invention further relates to certain novel intermediates useful in the preparation of compound of CCI-779 and processes for their preparation. The invention also relates to pharmaceutical compositions that include the compound of CCI-779, prepared according to the processes disclosed herein.
