Montmorillonite 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. ... 

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>. 

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

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... 

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. ... 

Villemin and Labiad (90SC3213) (Scheme 87) describe the dry condensation of pyrazol-3-one 62 with aromatic aldehydes 283a-d by adsorption on acidic Montmorillonite KSF clay under microwave irradiation (280W) to afford (Z)-284a-d and (7s)-4-arylmethylidenepyrazol-3-ones 285a-d in 85 (70/30), 77 (68/32), 68 (70/30), 71 (70/30), and 92% (Z/E ratio 54/41), yield and Z/E ratios, respectively. 

Scheme 93) condensed pyrazol-3-one 62 with 3-(2-furyl)acrolein 303 by adsorption on acidic Montmorillonite KSF clay under microwave irradiation and obtained (4E)-4-[(2Z)-304 and (4 ,)-4-[(2 )-3-(2-furyl)prop-2-enylidene]pyrazol-3-one 305 in 92% yield and 54/41 Z/E ratio. 

Significant rate and yield enhancements have been reported for Biginelli reactions performed under MW irradiation conditions. Most of these procedures are solvent-free and were performed in a domestic MW oven and require various catalysts such as polyphosphate ester (PPE) [59], Cu(II) salts [60], iodine-alumina [61], montmorillonite KSF clay [62, 63], or different chlorine-containing catalytic systems [64],... 

The desired a-aminophosphonates 69 can be synthesized by using an MCR approach under MW-accelerated conditions, however [126]. MW technology enables the use of the inexpensive and reusable montmorillonite KSF clay catalyst. Aromatic and aliphatic aldehydes both afforded excellent yields of products (80-92%) in short reaction times (3-5 min). Ketones gave the corresponding phospho-nates 69, also in good yields (65-80%) after an irradiation time of 6-8 min. 

Condensation of salicylaldehyde with malonic acid in the presence of montmorillonite KSF clay as a catalyst gave, under MWI for 12 min (Scheme 19),... 

When a mixture of 2-aminobenzophenone (314) and 1,3-cyclohexanedione (315) was adsorbed on montmorillonite KSF clay and irradiated in an MW oven for 5 min, acridine derivative 316 was obtained in 62% yield (Scheme 64). The yield was reduced on prolonged irradiation owing to thermal decomposition (99SC4403). 

A bimetallic catalyst based on Cu-Mn spinel oxide was used for azide-alkyne reactions. Microwave irradiation conditions were required due to its low intrinsic catalytic activity. It was observed that Mn significantly influenced the efficiency and selectivity of the bimetallic catalyst (Yousuf et al., 2010). Nanoporous Cu catalysts (CuNPore) can be employed for the efficient assembly of 1,2,3-triazoles (Jin et al., 2011). Additionally, their tunable ligament sizes have a significant impact on the catalytic activity. Bharate et al. reported a recyclable clay-supported, Cu(II)-catalyzed, one-pot synthesis of 1,2,3-triazoles (Mohammed et al., 2012). In this case, montmorillonite KSF clay-supported CuO nanoparticles efficiently promoted the one-pot aromatic azidonation of the arylboronic acids/azide-alkyne cycloaddition process at room temperature. 

Using montmorillonite KSF clay as the catalyst, Mitra et al. [85] prepared di-hydropyrimidinone derivatives. The reactants taken were P-keto esters, urea and different aliphatic and aromatic aldehydes. Depending upon the irradiation time, the yield varies from 80 to 98% (Scheme 11.32). 

Reaction conditions Dichloromethane / tetrahydrofuran (THF), room temperature Synthetic strategy One-step condensation Catalyst Montmorillonite-KSF clay / iodine... 

Method 1. Montmorillonite-KSF clay (1 g), amine (1 1.2 mmol), and hexane-2,5-dione (2 1 mmol) were mixed together thoroughly using dichloromethane (1 mL). The solvent was then evaporated out, and the mixture was kept at room temperature for specified period (10-25 h for varying entries). On completion of the reaction, the solid mixture was washed with dichloromethane and the washings were evaporated to obtain substituted pyrrole 3 followed by required purification (70-98% yield). 

By analogy to the standard synthesis of benzoxazoles (cf. p. 180), benzothiazoles are synthesized [360] by cyclocondensation of (2-amino)thiophenols with carboxylic acids or esters, with orthoesters in the presence of the acidic montmorillonite KSF clay catalyst, practicable also for the synthesis of benzoxazoles and benzimidazoles [361] or with aldehydes in the presence of an oxidant [362] ... 

Reddy et al. synthesized 5-hydroxyindole derivatives via the Nenitzescu reaction by coupling of aniline, ethyl acetoacetate, and p-benzoquinone, in 1,2-dichloroethane, using montmorillonite KSF clay as catalyst (Scheme 18) [87]. The reaction was also performed using acyclic and cyclic 1,3-diketones and with aryl and alkyl amines. Among several catalysts tested in this reaction, montmorillonite KSF clay proved to be the best catalyst leading to the highest yields in a shorter reaction time. 

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