KSF clay

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. ... 

One of the first published microwave-assisted synthesis of benzothiazoles is the condensation of a dinucleophile such as 2-aminothiophenol, with an ortho-ester (neat) in the presence of KSF clay in a mono-mode microwave reactor operating at 60 W under a nitrogene atmosphere [ 12] (Scheme 12). Traditional heating (oil bath, toluene as solvent and KSF clay) gave the expected products in similar yields compared to the microwave experiments but more than 12 h were required for completion. Solvent-free microwave-assisted syntheses of benzothiazoles was also described by attack of the dinucleophiles cited above on benzaldehydes and benzaldoximines [13] (Scheme 12). This methodology was performed in a dedicated monomode microwave reactor... 

Loupy and colleagues have prepared acetals of 1-galactono-l,4-lactone in excellent yields [31] by adsorbing the lactone and the aldehyde on montmorillonite K 10 or KSF clay followed by exposing the reaction mixture to microwave irradiation (Scheme 6.1). 

Aldehydes and ketones have been protected as acetals and dioxolanes using orthoformates, 1,2-ethanedithiol or 2,2-dimethyl-l,3-dioxolane by Hamelin and coworkers. This acid-catalyzed reaction proceeds in the presence of p-toluenesulfonic acid (p-TsOH) or KSF clay under solvent-free conditions (Scheme 6.2). The yields ob-... 

A facile deoximation procedure with sodium periodate impregnated on moist silica (Scheme 6.11) has also been introduced that is applicable exclusively to ketoximes [50], Aldehydes have been regenerated from the corresponding bisulfites (85-98%) on KSF clay surface [51]. 

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>. 

Yadav and co-workers have described a general method for the reaction between benzaldehyde, benzylamine and diethyl phosphite. In the presence of KSF clay, a-amino phosphonates were formed in a few minutes under microwave irradiation, Scheme 5.35. 

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

Phenylethanol lc (1.2 g, 10 mmol) and 3-ethoxypropionitrile 2d (1 g, 10 mmol) were admixed with KSF clay (1.2 g, w/w of alcohol) and subjected to microwave irradiation in a Pyrex test tube for 3 min. Then the reaction mass was cooled to room temperature, charged on a short silica gel column (Merck, 200 mesh) and eluted (ethyl acetate-n-hexane, 2 8) to afford the pure amide as a pale yellow liquid (2.05 g, 93%). 

Keywords orthoester, -substituted aminoaromatics, KSF clay, microwave irradiation, benzimidazole, benzoxazole, benzthiazole... 

A mixture of 2-aminoaromatic 1 (10 mmol), orthoester 2a or 2b (10 mmol) and KSF clay (2 g) in a Pyrex tube under nitrogen was mixed and then irradiated in a focused microwave cavity (cavity E013 of MES) for 5 min with a power of 60 W. The mixture was extracted with CH2CI2 (3x20 mL) and the solvent was evaporated in vacuum. The residue was distilled or recrystallized. 

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%). 

The alcohol 1 (3 mmol) in solution in CH2CI2 was absorbed onto KSF clay (1 g), solvent was evaporated in vacuo. The solid was irradiated by microwaves (270 W, 5 min) in a sealed Teflon vessel and after cooling at room temperature, was extracted by elution with MeCN. The product was recrystallized from ethanol after evaporation of the solvent (95%). 

Sydnones 78 (R1 = Ph, Ar or 3-pyridyl, R3 = H or Me) are obtained from the nitrosoamino acids 77 and acetic anhydride under ultrasound (94MI153). Three examples of the formation of oxadiazoles by microwave irradiation are from O-acyl amide oximes 79 in the presence of aluminium oxide, from amide oximes 80 and isoprop-enyl acetate in the presence of KSF-clay and from N,N -diacylhydrazines 81 and thionyl chloride (95SC1451). 

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... 

The octahydroquinolines 24 and decahydroacridines were obtained from dimedone. On montmorillonite KSF clay, acridine derivatives 25 were obtained. Reaction of arylidenemalononitriles with cyclic ketones gave 2-amino-3-cyanopyridines 26. Reaction of diphenylamine and dicarboxylic acids or arylacetic acids was catalyzed by zinc chloride to give acridines. Pyrimido[4,5-Z>]quinolines 27 were synthesized. ... 

Montmorillonite KSF clay, reflux, CHsCN. In this case, an N-BOC group is retained. In other cases, f-Bu esters are somewhat more stable to acid than are N-BOC derivatives. ... 

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