Montmorillonite KSF

Dimethyl-1,3-dioxolane, microwave irradiation. Montmorillonite KSF, 38-95% yield.""... 

Some work has also been achieved with heterogeneous catalysis. These catalysts include Amberlyst-15, Nafion-H, montmorillonite KSF clay, ferrihydrite silica gel aerogels containing 11-13% iron, silica sulfuric acid, and zeolites. ... 

Bigi F, Chesini L, Maggi R, Sartori G (1999) Montmorillonite KSF as an inorganic, water stable, and reusable catalyst for the knoevenagel synthesis of coumarin-3-carboxylic acids. J Org Chem 64 1033-1035... 

Yadav et al.110 employed montmorillonite KSF as a catalyst for the reaction of arylamines with 2-deoxy-D-eryf/tro-pentose. The reaction took place on the surface of the catalyst and proceeded with cyclization to afford sugar-derived chiral tetrahydro-quinolines in high yields and moderate diastereoselectivity. 

This conclusion is in agreement with the kinetic results from Radoiu et al. [86] obtained for the transformation of 2- and 4-tbutyl phenols in the liquid phase in the presence of montmorillonite KSF as catalyst either under the action of MW or A (Eq. (31) and Tab. 3.12). 

Use of montmorillonites KSF or K10 as acidic supports and irradiation at 60 W (monomode oven, final temperature 155 °C) led to yields threefold higher in 10 min. 

Samajdar et al. (2000) performed nitration of aromatic compounds by bismnth nitrate on catalysis with montmorillonite KSF. The reaction develops in THF suspension on steering dnring 10 min. Nitration of anisole proceeds strictly in the para position (91% yield after 10 min), bnt in case of phenol, the reaction occnrs to be nonregioselective and 3 1 mixture of para and ortho nitro prod-nets is formed with a common yield of 89%. Nitration of estrone (the steroid phenol) also leads to 1 1 mixtnre of para and ortho nitrophenolic steroids in 94% yield. 

The Pechmann and Knoevenagel reactions have been widely used to synthesise coumarins and developments in both have been reported. Activated phenols react rapidly with ethyl acetoacetate, propenoic acid and propynoic acid under microwave irradiation using cation-exchange resins as catalyst <99SL608>. Similarly, salicylaldehydes are converted into coumarin-3-carboxylic acids when the reaction with malonic acid is catalysed by the montmorillonite KSF <99JOC1033>. In both cases the use of a solid catalyst has environmentally friendly benefits. Methyl 3-(3-coumarinyl)propenoate 44, prepared from dimethyl glutaconate and salicylaldehyde, is a stable electron deficient diene which reacts with enamines to form benzo[c]coumarins. An inverse electron demand Diels-Alder reaction is followed by elimination of a secondary amine and aromatisation (Scheme 26) <99SL477>. 

Aryl amines react with an excess of an endocyclic ene-carbamate, including tert- mVf 1,2,3,4-tetrahydro-l-pyridi-necarboxylate, on the surface of Montmorillonite KSF clay to give 4-aminobutyloctahydrobenzo[ ][l,6]naphthyr-idines in excellent yields and moderate diastereoselectivity <2004TL7947>. 

Bowe CA, Krikorian N, Martin DF. Extraction of Heavy Metals Using Modified Montmorillonite KSF. Florida Scientist 2004 67 74-79. 

Aldehyde 1 (10 mmol), / -dicarbonyl compound 2 (10 mmol), urea 3 (0.9 g, 15 mmol) and montmorillonite KSF (0.5 g) were heated at 130 °C under stirring for 48 h. Hot methanol (100 mL) was added and the mixture was filtered to remove die catalyst. Products 4 crystallized after several horns and were recovered by filtration. 

Keywords benzaldehyde, acetophenone, montmorillonite KSF, clay, tram-chal-cone... 

Montmorillonite KSF (1.0 g), the selected benzaldehyde 1 (0.010 mol) and the selected acetophenone 2 (0.010 mol) were placed in a small autoclave and heated at 130 °C for 18 h. After cooling to room temperature, 95% ethanol (25 mL) was added, the mixture was filtered, the catalyst washed with hot 95% ethanol (25 mL) and the products crystallized from the same solvent. All the products gave melting points and spectral data consistent with the reported data. 

Keywords barbituric acid, aromatic aldehyde, montmorillonite KSF, microwave irradiation, condensation... 

Barbituric acid 1 (5 mol), aldehyde 2 (6 mmol) and montmorillonite KSF (1 g) were ground with solid aldehyde or were mixed with liquid aldehyde. The mixture placed in an open Pyrex Erlenmeyer flask (25 mL) was irradiated with a microwave oven. After cooling the product was extracted with DMF (15 mL) and the solvent was evaporated in vacuo. The resulting solid was ground and washed with ether (30 mL), filtered and dried. 

Keywords alcohol, nitrile, montmorillonite KSF, Ritter reaction, microwave irradiation, amide... 

Aldehyde/ketone (5 mmol), amine (5 mmol), diethyl phosphite (5 mmol) and montmorillonite (1.5 g, Aldrich, montmorillonite, KSF) were admixed in a Pyrex test tube and exposed to microwave irradiation at 450 W using a (BPL, BMO, 700T, indicates the commercial name of microwave oven) focused microwave oven for an appropriate time (pulsed irradiation 1 min with 20 s interval). After complete conversion of the reaction, as indicated by TLC, the reaction mixture was directly charged on a small silica gel column and eluted with a mixture of ethyl acetate-hexane (3 7) to afford corresponding pure a-amino phosphonate. 

The a-phenoxy acetophenone 2 (212 mg, 1 mmol) was dissolved in minimum amount of dichloromethane, adsorbed over montmorillonite KSF clay (sub-strate clay=l 2 w/w). It was transferred into a test tube and subjected to micro-wave irradiation (BPL make, BMO 700T, 650 W, high power). The reaction was monitored by TLC. After completion of the reaction (6 min) it was leached with dichloromethane (3x 10 mL). The solvent was evaporated under reduced pressure and purified through column chromatography using ethyl acetate-hexane (9 1) to give 3-phenylbenzofuran (165 mg, 85%). 

Keywords bisulfite, montmorillonite KSF clay, microwave irradiation, aldehyde... 

A mixture of bisulfite addition product (1 mmol) and montmorillonite KSF (300 mg) was taken in a 25-mL Erlenmeyer flask and kept over an alumina bath (heat sink) inside a domestic microwave oven and irradiated for 520 s and the reaction was monitored by TLC. The product was extracted with ethyl acetate (2x 5 mL), washed with brine and dried over anhydrous sodium sulfate. Evaporation of the solvent afforded the products in excellent yield. All the products were characterized by 1H NMR spectroscopy and by comparison with IR spectra of authentic samples. 

Montmorillonite KSF 3g avoid contact with skin and eyes... 

The diamine (3 mmol) in acetonitrile or THF (15 ml) is added with shaking to the argile (e.g. montmorillonite KSF or bentonite KIO) at room temperature ( 5 min). The solvent is then removed below 50°C. The solid impregnated with the diamine is then placed in a Pyrex tube (2 x 15 cm), and while stirring with a glass rod, ethyl acetoacetate or ethyl benzoylacctate (4 mmol) is added and the mixture is microwaved at 490 W (4 min). The benzimidazole products arc extracted firam the support with acetone, and ultimately recrystallized from xylene. 

The most common method for the preparation of pyrazoles from other heterocycles is from pyranone-type compounds. Condensation of 2,3-dihydro /7-pyran -ones 787 with various aryl hydrazines in the presence of montmorillonite KSF clay under mild conditions proceeded rapidly to afford enantiomerically pure 5-substituted pyrazoles 788 (Equation 172) <2004TL6033>. Comparable results were obtained when arylhydrazines were reacted with 2-formyl glycals under microwave irradiation <2004TL8587>. Phenylhydrazine and hydrazine were reacted with 3-acetyl-4-hydroxy-6-methyl-2/7-pyran-2-one to afford 4-acetoacetyl-3-methylpyrazolin-5-ones, which were employed in the synthesis of bipyrazoles and pyrazoloisoxazoles <1999JHC1291>. Reaction of 3,3-dialkyl-6-(trifluoromethyl)-2,3-dihy-dro -pyrones with hydrazine hydrate afforded 3-(trifluoromethyl)-5-substituted-pyrazoles <1998RCB1365>. 

Samarium iodide promotes this addition reaction. " " In a related reaction, simple alkene units add to esters in the presence of sodium and liquid ammonia to give an alcohol.Structural variations in the alkene lead to different products. Homo-allylic alcohols react with aldehydes in the presence of Montmorillonite KSF clay to give 4-hydroxytetrahydropyrans. " A variation of this reaction converts an aryl aldehyde and a homoallylic alcohol to a 4-chlorotetrahydropyran in the presence of Homoallylic alcohols, protected as —O(CHMeOAc) react with... 

Acetaldoxime was converted to acetonitrile in about 80% yield over an H-ZSM-5 catalyst at 300°C (Eqn. 22.23).5 Heating aldoximes with montmorillonite KSF in refluxing toluene gave the nitriles in 65-85% yields. Rupe Reaction... 

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