- A highly efficient and chemoselective method for acetalization of carbonyl compounds catalyzed by TiO2/SO42- solid superacid
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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.
- Ma, Yan-Ran,Jin, Tong-Shou,Shi, Sheng-Xun,Li, Tong-Shuang
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Read Online
- Catalysis of a peptidic micellar assembly covalently immobilized within mesoporous silica channels: Importance of amphiphilic spatial design
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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).
- Otani, Wataru,Kinbara, Kazushi,Zhang, Qingmin,Ariga, Katsuhiko,Aida, Takuzo
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Read Online
- Practical acetalization and transacetalization of carbonyl compounds catalyzed by recyclable PVP-I
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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.
- Cao, Fu-Rong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
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- A novel, mesoporous molybdenum doped titanium dioxide/reduced graphene oxide composite as a green, highly efficient solid acid catalyst for acetalization
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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.
- He, Junkai,Kankanam Kapuge, Tharindu,Kerns, Peter,Meguerdichian, Andrew G.,Suib, Steven L.,Thalgaspitiya, Wimalika R. K.
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p. 3786 - 3795
(2020/04/03)
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- 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
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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.
- Sharp, Phillip P.,Mikusek, Jiri,Ho, Junming,Krenske, Elizabeth H.,Banwell, Martin G.,Coote, Michelle L.,Ward, Jas S.,Willis, Anthony C.
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p. 13678 - 13690
(2018/11/10)
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- Method for catalytic synthesis of cyclohexanone ethylene ketal from titanium phosphotungstate and ammonium phosphotungstate composite salt
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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.
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Paragraph 0021-0031
(2018/07/30)
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- A Lamellar Coordination Polymer with Remarkable Catalytic Activity
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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.
- Mendes, Ricardo F.,Antunes, Margarida M.,Silva, Patrícia,Barbosa, Paula,Figueiredo, Filipe,Linden, Anthony,Rocha, Jo?o,Valente, Anabela A.,Almeida Paz, Filipe A.
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p. 13136 - 13146
(2016/09/09)
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- Mixed (Fe2+ and Cu2+) double metal hexacyanocobaltates as solid catalyst for the aerobic oxidation of oximes to carbonyl compounds
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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.
- Garcia-Ortiz, Alma,Grirrane, Abdessamad,Reguera, Edilso,Garcia, Hermenegildo
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p. 386 - 392
(2014/02/14)
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- Zeolite nanofiber assemblies as acid catalysts with high activity for the acetalization of carbonyl compounds with alcohols
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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.
- Liu, Taotao,Fu, Wenqian,Zheng, Xiang,Jiang, Jun,Hu, Maolin,Tang, Tiandi
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p. 18217 - 18221
(2014/05/20)
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- PROCESS FOR THE PREPARATION OF RAPAMYCIN DERIVATIVES
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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.
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Page/Page column 13
(2012/08/27)
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- Synthesis of Acetals Containing a Primary Amino Group
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Amino acetals of the general formula MeCH(OR)(OXNH2) (R = Et, Bu, X = CH2CH2, CH2CH2CH 2, CH2CMe2) were synthesized in 53-91% yield by acid-catalyzed reaction of N-(2-hydroxyethyl)-, N-(3-hydroxypropyl)-, and N-(2-hydroxy-1,1-dimethylethyl)-2,2,2-trifluoroacetamides with vinyl ethers, followed by removal of the trifluoroacetyl protection by alkaline hydrolysis. Pleiades Publishing, Ltd., 2012.
- Lobanova,Stankevich,Kukharev
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p. 1289 - 1296
(2013/02/21)
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- One-Step synthesis of acetals from phenol/alcohols mixtures using a Pd/Aluminoborate catalyst
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A one-step synthesis of cyclohexanone acetals from phenol/alcohol mixtures has been explored using bifunctional aluminum borates supported Pd catalysts. Three aluminum borates have been prepared via either a high temperature calcination (9Al2O3·2B2O3) or a selfpressured thermal synthesis (PKU-1 and ABO-X) using various aluminum precursors and boric acid. Well dispersed Pd nanoparticles loaded on these materials show excellent phenol hydrogenation activity in both water and ethanol. The reactivity follows the trend of Pd/ABOX[ Pd/9Al2O 3·2B2O3[Pd/PKU-1, which is similar to the sequence of BO4/BO3 ratio presented in the aluminoborates as shown by NMR spectra. When ethanol is used as a solvent, 13.5 % yield of cyclohexanone diethyl acetal has been obtained under the conditions investigated on Pd/ ABO-X, which is attributed to its high activity in both hydrogenation and acetalization for the one-step synthesis of cyclohexanone acetals. Springer Science+Business Media New York 2012.
- Guan, Yejun,Zhang, Damin,Wang, Yimeng
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p. 1225 - 1233
(2013/01/15)
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- PROCESS FOR THE PREPARATION OF RAPAMYCIN DERIVATIVES
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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.
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Page/Page column 25
(2011/05/11)
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- The use of anhydrous CeCl3 as a recyclable and selective catalyst for the acetalization of aldehydes and ketones
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An efficient, clean, chemoselective and solvent-free method for the synthesis of ketone and aldehyde dimethyl acetals was developed using trimethyl orthoformate and commercially available anhydrous CeCl3 as a recyclable catalyst. The method is general and affords the protected carbonyl compounds in good yields and under mild conditions, including aryl and alkyl ketones and activated aldehydes. The catalyst could be utilised directly for 3 cycles, without significant loss of activity.
- Silveira, Claudio C.,Mendes, Samuel R.,Ziembowicz, Francieli I.,Lenarda?o, Eder J.,Perin, Gelson
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body text
p. 371 - 374
(2010/09/07)
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- A facile procedure for acetalization of aldehydes and ketones catalyzed by cerium(III) trifluoromethanesulfonate
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Aldehydes and ketones are readily protected in the presence of trialkyl orthoformate and a catalytic amount of cerium(III) trifluoromethanesulfonate under mild conditions to give the corresponding acetals in good to excellent yields. Due to the mild reaction conditions, this method is compatible with acid-sensitive substrates. Copyright
- Ono, Fumiaki,Inatomi, Yoshiko,Tada, Yuusuke,Mori, Masaki,Sato, Tsuneo
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experimental part
p. 96 - 97
(2009/11/30)
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- Highly regioselective synthesis of trifluoromethyl derivatives of pyrazolo[1,5-a]pyrimidines bearing fused cycloalkane rings using (2-ethoxycycloalkenyl)-2,2,2-trifluoroethanones
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8-Trifluoromethyl-6,7-dihydro-5H-1,4,8a-triaza-s-indacene and 9-trifluoromethyl-5,6,7,8-tetrahydropyrazolo[5,1-b]quinazolines were efficiently generated by condensation of 5(3)-aminopyrazoles with (2-ethoxycycloalkenyl)-2,2,2-trifluoroethanones and isolated in excellent yields. The regiochemistry of the prepared compounds was established by 1H, 13C and 19F NMR spectroscopy and X-ray diffraction analysis.
- Emelina, Elena E.,Petrov, Aleksander A.,Selivanov, Stanislav I.,Nelyubina, Yulia V.,Antipin, Mikhail Yu.
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experimental part
p. 861 - 869
(2009/12/30)
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- One-pot synthesis of functionalized 3-(trifluoromethyl)phenols by [3+3] cyclization of 1,3-bis(silyl enol ethers) with α,β-unsaturated trifluoromethyl ketones
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Functionalized 3-(trifluoromethyl)phenols were prepared by formal [3+3] cyclization of 1,3-bis(silyl enol ethers) with readily available open-chained and cyclic α,β-unsaturated trifluoromethyl ketones. The reaction of 3,4-dihydro-5-(trifluoroacetyl)-2H-pyran with 1,3-bis(silyl enol ethers) resulted in a domino process to give new functionalized dihydropyrans. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Mamat, Constantin,Pundt, Thomas,Dang, T. H. Tam,Klassen, Renske,Reinke, Helmut,Koeckerling, Martin,Langer, Peter
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p. 492 - 502
(2008/09/18)
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- Iron(III) tosylate in the preparation of dimethyl and diethyl acetals from ketones and β-keto enol ethers from cyclic β-diketones
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An efficient method for conversion of ketones to their corresponding dimethyl and diethyl acetals and of cyclic β-diketones into β-keto enol ethers using Fe(OTs)3 as a catalyst is described. Copyright Taylor & Francis Group, LLC.
- Mansilla, Horacio,Afonso, Maria M.
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p. 2607 - 2618
(2008/12/22)
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- Simple method for the preparation of dimethyl acetals from ketones with montmorillonite K 10 and p-toluenesulfonic acid
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A simple method for conversion of ketones to their corresponding dimethyl acetals using montmorillonite K 10 and p-toluenesulfonic acid as acidic cocatalysts under very mild reaction conditions is described. Copyright Taylor & Francis Group, LLC.
- Mansilla, Horacio,Regas, David
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p. 2195 - 2201
(2007/10/03)
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- Acid-free, organocatalytic acetalization
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The acid-free, organocatalytic acetalization of various aldehydes and ketones with N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is presented. The neutral, double hydrogen bonding thiourea catalyst can be used at very low loadings of 0.01-1 mol% at room temperature to furnish the respective acetals in 65-99% yield at turnover frequencies around 600 h-1. Acid-labile TBDMS-protected as well as unsaturated aldehydes can be converted efficiently into their acetals utilizing this very mild and highly practical method.
- Kotke, Mike,Schreiner, Peter R.
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p. 434 - 439
(2007/10/03)
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- Bronsted acidic ionic liquids as efficient and recyclable catalysts for protection of carbonyls to acetals and ketals under mild conditions
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A series of acidic ionic liquids have been used as efficient catalysts for the protection of various carbonyl compounds at room temperature. The features of mild conditions, satisfactory isolated yield, simple workup, and the recyclability of the catalyst were present in this process. Copyright Taylor & Francis, Inc.
- Du, Yuying,Tian, Fuli
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p. 2703 - 2708
(2007/10/03)
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- Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for acetal formation
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Commercially available copper(II) tetrafluoroborate hydrate has been found to be a highly efficient catalyst for dimethyl/diethyl acetal formation in high yields from aldehydes and ketones by reaction with trimethyl/triethyl orthoformate at room temperature and in short period. Acetalisation was carried out under solvent-free conditions with electrophilic aldehydes/ketones. For weakly electrophilic aldehydes/ketones (e.g., benzaldehyde, cinnamaldehyde and acetophenone) and for aldehydes having a substituent that can coordinate with the catalyst, the corresponding alcohol was used as solvent.
- Kumar, Raj,Chakraborti, Asit K.
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p. 8319 - 8323
(2007/10/03)
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- High-pressure-promoted uncatalyzed ketalization of ketones and oxy-Michael/ketalization of conjugated enones
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A new practical method for ketalization or oxy-Michael/ketalization was developed using the high-pressure-promoted condensation of ketones or α,β-unsaturated ketones with alcohols in the presence of trialkyl orthoformates as water scavengers. Georg Thieme Verlag Stuttgart.
- Kumamoto, Koji,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
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p. 2254 - 2256
(2007/10/03)
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- Sulfamic acid as a cost-effective and recyclable catalyst for protection of carbonyls to acetals and ketals under mild conditions
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An efficient H2NSO3H-catalyzed protection of various carbonyl compounds at room temperature was investigated. The features of mild conditions, cost-efficient catalyst, simple workup, and the recyclability of the catalyst were represented in this process.
- Gong, Weizhong,Wang, Bo,Gu, Yanglong,Yan, Liang,Yang, Liming,Suo, Jishuan
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p. 4243 - 4247
(2007/10/03)
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- An efficient and versatile procedure for the synthesis of acetals from aldehydes and ketones catalyzed by lithium tetrafluoroborate
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Acetals are obtained in good to excellent yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of a catalytic amount of lithium tetrafluoroborate. Due to the mild reaction conditions, this method is compatible with acid-sensitive substrates.
- Hamada, Nao,Kazahaya, Kiyoshi,Shimizu, Hisashi,Sato, Tsuneo
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p. 1074 - 1076
(2015/10/07)
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- 2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO) as a versatile, efficient, and chemoselective catalyst for the acetalization and transacetalization of carbonyl compounds, the preparation of acetonides from epoxides and acylals (1,1-diacetates) from aldehydes
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The efficient and chemoselective preparation of acetals and ketals from carbonyl compounds, transacetalization reactions, the conversion of epoxides to acetonides, and the preparation of acylals from aldehydes in the presence of catalytic amounts of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO) are described.
- Firouzabadi, Habib,Iranpoor, Nasser,Shaterian, Hamid Reza
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p. 2195 - 2205
(2007/10/03)
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- Tetrabutylammonium tribromide (TBATB) as an efficient generator of HBr for an efficient chemoselective reagent for acetalization of carbonyl compounds
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Acyclic and cyclic acetals of various carbonyl compounds were obtained in excellent yields under a mild reaction condition in the presence of trialkyl orthoformate and a catalytic amount of tetrabutylammonium tribromide (TBATB) in absolute alcohol. Chemoselective acetalization of an aldehyde in the presence of ketone, unsymmetrical acetal formation, shorter reaction times, mild reaction conditions, the stability of acid-sensitive protecting groups, high efficiencies, facile isolation of the desired products, and the catalytic nature of the reagent make the present methodology a practical alternative.
- Gopinath, Rangam,Haque, Sk. Jiaul,Patel, Bhisma K.
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p. 5842 - 5845
(2007/10/03)
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- A simple and versatile method for the synthesis of acetals from aldehydes and ketones using bismuth triflate
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Acetals are obtained in good yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of 0.1 mol % Bi(OTf)3·4H2O. A simple procedure for the formation of acetals of diaryl ketones has also been developed. The conversion of carbonyl compounds to the corresponding 1,3-dioxolane using ethylene glycol is also catalyzed by Bi(OTf)3· 4H2O (1 mol %). Two methods, both of which avoid the use of benzene, have been developed.
- Leonard, Nicholas M.,Oswald, Matthew C.,Freiberg, Derek A.,Nattier, Bryce A.,Smith, Russell C.,Mohan, Ram S.
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p. 5202 - 5207
(2007/10/03)
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- A new molecular iodine-catalyzed acetalization of carbonyl compounds
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A new and facile molecular iodine-catalyzed acetalization of carbonyl compounds has been developed. Useful selectivity has also been demonstrated.
- Basu, Manas K.,Samajdar, Susanta,Becker, Frederick F.,Banik, Bimal K.
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p. 319 - 321
(2007/10/03)
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- Facile synthesis of enol ethers by cleavage of α-bromoacetals and α-bromoketals mediated by SmI2
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α-Bromocyclicacetals, α-bromocyclicketals and α-bromocyclicthioketals, derived from cyclic and acyclic ketones and aldehydes, reacted with samarium diiodide at -78°C in THF to furnish the corresponding enol ethers or thioenol ethers containing hydroxy or thiol moieties in high yields.
- Park, Heui Sul,Kim, Seong Ho,Park, Min Young,Kim, Yong Hae
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p. 3729 - 3732
(2007/10/03)
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- New routes to diethyl 1-alkenylphosphoramidates
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New routes to N-(diethoxyphosphoryl)imines derived from enolizable carbonyl compounds have been investigated. Three different procedures were studied: (i) the aza-Claisen condensation of ethyl-[N-(diethoxyphosphoryl)]-formimidate with enolizable ketones, (ii) the reaction between diethyl N-sulfinylphosphoramidate and aliphatic aldehydes, and (iii) the thermally induced reaction of diethyl phosphoramidate with ketone diethyl acetals. With two exceptions in all cases the products were identified as diethyl 1-alkenylphosphoramidates with no spectroscopically detectable amounts of imine tautomers. The aza-Claisen condensation can be recommended as a simple and effective route to diethyl 1-alkenyl-3-oxophosphoramidates. (C) 2000 Elsevier Science Ltd.
- Napieraj, Anna,Zawadzki, Stefan,Zwierzak, Andrzej
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p. 6299 - 6305
(2007/10/03)
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- Synthesis and crystal structures of two potential gem-di(pyrazolyl)cycloalkane ligands, 1,1-di(pyrazol-1-yl)cyclohexane [C6H10(C3N2H3)2] and 1,1-di(pyrazol-1-yl)cyclopentane [C5H8(C3N2H3)2]
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The species 1,1-di(pyrazol-1-yl)cyclohexane, C12H16N4, crystallizes in the monoclinic space group P21/c with a = 8.340(2), b = 14.281(5), c = 10.153(3) A, β= 106.86(2)°, and Z = 4. The cyclohexane moiety has the chair conformation. The congener, 1,1-di(pyrazol-1-yl) cyclopentane, C11H14N4, while not isomorphous, also crystallizes in space group P21/c with a = 14.350(2), b = 6.776(1), c = 11.043(2) A, β= 100.68(1)°, and Z = 4. The cyclopentane ring has a conformation in which four carbon atoms are essentially coplanar, while the fifth (that with the two pyrazolyl substituents) lies 0.63 A from this plane, resulting in a bend of 41.3° across the C(2)...C(5) vector. The hydrogen atoms in each structure were located directly and their coordinates refined.
- Churchill, Melvyn Rowen,Churchill, David George,Huynh, My Hang Vo,Takeuchi, Kenneth J.,Distefano, Alison J.,Jameson, Donald L.
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p. 659 - 665
(2007/10/03)
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- A novel reaction medium: Perfluorocarbon fluids
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The use of perfluorocarbon (PFC) fluids such as perfluorinated alkanes and alkylamines as inert medium for organic reactions is demonstrated with advantages summarized. PFC fluids have been found to be very useful in organic reactions where a medium is needed for refluxing and for separating a low boiling component, or where an extremely nonpolar/inert medium is required for reactions carried out under vigorous conditions. The PFC fluids are not miscible with most organic compounds and therefore offer good separatory properties that common organic solvents do not have.
- Zhu
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p. 953 - 954
(2007/10/02)
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- Synthesis of racemic 3-methylphosphonate analogues of myo-inositol 3,4-bis- and 1,3,4-trisphosphate
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The partially benzyl protected myo-inositol derivatives 11a and 11b, the C-4 and C-1,4 hydroxyl function(s) of which are protected with temporary trans-prop-1-enyl protecting group(s), were readily converted into the respective title compounds 18a and 18b by sequential methylphosphonylation, mild cleavage of the trans-prop-1-enyl group(s), phosphorylation and removal of all permanent benzyl protecting groups.
- Dreef,Tuinman,Lefeber,Elie,Van Der Marel,Van Boom
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p. 4709 - 4722
(2007/10/02)
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- A simple, one-flask transformation of ketones to N-methyl lactams
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A one-flask conversion of cyclic ketones to N-methyl lactams is described. Reaction of the ketone with triethylorthoformate generates an acetal which is reacted in situ with N-(((p-nitrobenzene)sulfonyl)oxy methylamine 2a(CH3NH-OSO2C6H4NO2). Dealkylation of the resulting O-ethyl imidate with sodium iodide gives the lactam. A variety of lactams, including macrocyclic lactams, are produced simply and in good yields.
- Hoffman, Robert V.,Salvador, James M.
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p. 2429 - 2432
(2007/10/02)
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- A versatile rhodium catalyst for acetalization reactions under mild conditions
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Carbonyl compounds are readily acetalized under mild conditions in the presence of catalytic amounts of Rh(III)triphos moieties.
- Ott,Ramos Tombo,Schmid,Venanzi,Wang,Ward
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p. 6151 - 6154
(2007/10/02)
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- A Versatile Synthesis of Four-, Five-, and Six-membered Cyclic Ketones Using Methyl Methylthiomethyl Sulfoxide
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Cyclization of 1,n-dihaloalkanes with methyl methylthiomethyl sulfoxide in the presence of a base (n-BuLi or KH) gave three-, four-, five-, and six-membered 1-methylsulfinyl-1-methylthiocycloalkanes.These cyclization products were easily converted to the corresponding ketones by acid hydrolysis except 1-methylsulfinyl-1-methylthiocyclopropane which afforded a complicated mixture.The combination of the cyclization with the acidhydrolysis thus provides a new method for synthesizing four-, five-, and six-membered cycloalkanones.Several representative preparations, such as those of substituted cyclobutanones, 3-cyclopentanone, and tetrahydro-4-pyrone are described.
- Ogura, K.,Yamashita, M.,Suzuki, M.,Furukawa, S.,Tsuchinashi, G.
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p. 1637 - 1642
(2007/10/02)
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- Polyhydroxyamino Compounds via Diene Synthesis with Nitroso Compounds, IV. - Preparation and Stereochemistry of Dideoxyinosamine Derivatives
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The general method for the synthesis of polyhydroxy amines by Diels-Alder reactions with a nitroso compound, reduction of the adduct with cleavage of the N - O bond and hydroxylation of the remaining C = C -double bond, can also be realized with α-chloronitrosocyclohexane as dienophile, in good yield.Primary amines are synthesized in this way.
- Kresze, Guenter,Kysela, Ernst
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p. 202 - 209
(2007/10/02)
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- Polyhydroxyamino Compounds via Diene Synthesis with Nitroso Compounds, VII. - Synthesis of Conduramine-F1
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A two-step synthesis of conduramine-F1 with trans-1,3-cyclohexadien-5,6-diyldiacetat (1) as educt is described.
- Kresze, Guenter,Dittel, Werner
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p. 610 - 611
(2007/10/02)
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- Cyclic ketone mercaptal S-oxides
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Novel cyclic ketone mercaptal S-oxides and a process for preparing these compounds which comprises reacting formaldehyde mercaptal S-oxides with specific difunctional compounds.
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