Preparation of ethyl b-arylamino crotonates using Keggin heteropolyacid supported on SiMCM-41 as catalysts.

L. PIZZIO; G. ROMANELLI,; P. VÁZQUEZ,; J. AUTINO,; M. BLANCO,; C. CÁCERES.

París, Francia

Congreso; 13th International Congress on Catálisis; 2004

The catalysts based on heteropolyacids with Keggin structure (HPA) and related compounds are less corrosive and produce lower amount of wastes than conventional acid catalysts, so they can be used as replacement in ecofriendly processes. The HPA were supported on several carriers in order to use these catalysts in heterogeneous liquid reactions , with the advantage of easy product recovery. The behavior of SiMCM-41 supported tungstophosphoric (TPA) and molybdophosphoric (MPA) acids in the esterification of acetic acid with isoamyl alcohol was studied. The surface of this support was also modified by attachment of amino groups to the siloxy groups, to avoid the HPA leaching. On the other hand, 4-quinolones are important compounds and valuable synthetic intermediates for derivatives that have biological activities belonging to various types, e. g. tuberculostatic. Some 4-quinolones are used as antibacterials, e. g. ciprofloxacin and other 6-fluoroquinolones. The Conrad-Limpach reaction between anilines and a â-ketoester is a general method to synthesize 4-quinolones. The aromatic amines react with methyl acetoacetate yielding alkyl â-arylaminocrotonates, acetoacetanilides, diphenylureas or 4- quinolones, depending on the temperature, solvent and molar ratio of the reactants. In this work we describe a simple procedure for the selective preparation of â-arylaminocrotonates, using TPA and MPA supported on SiMCM-41 and amino functionalized SiMCM- 41 as catalysts. These compounds can be cyclized to 4-quinolones by heating in diphenyleter.â-ketoester is a general method to synthesize 4-quinolones. The aromatic amines react with methyl acetoacetate yielding alkyl â-arylaminocrotonates, acetoacetanilides, diphenylureas or 4- quinolones, depending on the temperature, solvent and molar ratio of the reactants. In this work we describe a simple procedure for the selective preparation of â-arylaminocrotonates, using TPA and MPA supported on SiMCM-41 and amino functionalized SiMCM- 41 as catalysts. These compounds can be cyclized to 4-quinolones by heating in diphenyleter.â-arylaminocrotonates, acetoacetanilides, diphenylureas or 4- quinolones, depending on the temperature, solvent and molar ratio of the reactants. In this work we describe a simple procedure for the selective preparation of â-arylaminocrotonates, using TPA and MPA supported on SiMCM-41 and amino functionalized SiMCM- 41 as catalysts. These compounds can be cyclized to 4-quinolones by heating in diphenyleter.â-arylaminocrotonates, using TPA and MPA supported on SiMCM-41 and amino functionalized SiMCM- 41 as catalysts. These compounds can be cyclized to 4-quinolones by heating in diphenyleter.