The mechansim of the three-component Biginelli dihydropyrimidine synthesis was reinvestigated using (1)H and (13)C NMR spectroscopy. Condensation of benzaldehyde, ethyl acetoacetate, and urea (or N-methylurea) in CD(3)OH according to the procedure described by Biginelli produced the expected 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylates. According to NMR measurements, ther...

in recent years, the effects of heterogeneous catalysts for the oxidation of organic and inorganic pollutants in industrial wastewaters are spread. traditionally, these reactions are usually carried out using suspensions of photo-catalysts such as tio2. a chemical method including ticl4, al(no3)3, ethanol amine, ethyl acetoacetate and aqueous ammonia were used for the fabrication of tio2-al2o3 ...

The title compound, C(18)H(19)NO(5), is a product of the Hantzsch reaction of p-phthalaldehyde, methyl acetoacetate, and ammonium acetate. The 1,4-dihydro-pyridine ring of the mol-ecule adopts a flattened boat conformation. The benzene ring is almost perpendicular to the 1,4-dihydro-pyridine ring; the plane through the six C atoms of the benzene ring and the plane through the four C atoms that ...

cellulose was applied as a reusable and green catalyst for the facile four-component synthesis of 6-amino-4-aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives using hydrazine monohydrate, ethyl acetoacetate, malononitrile and aryl aldehydes, under solvent-free and thermal conditions. the use of non-toxic and inexpensive catalyst, short reaction time, clean work-up and goo...

3-Methyl-5-chloro-1-phenylpyrazol and its derivatives were prepared by the reaction with 3methyl -1-phenylpyrazol-5-one, phosphorous oxytrichloride and N-N dimethyl aniline respectively using catalyst. These compounds were further treated with alcohols and sodium hydroxide to form ether linkage. Ethyl acetoacetate reacted with phenylhydrazine at reflux temprature to give 3-methyl-1phenylpyrazol...

Two efficient and convenient procedures for the synthesis of 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano[2,3c]pyrazole-5-carbonitrile derivatives based on four-component reaction involving ethyl acetoacetate, phenylhydrazine, malononitrile, and various aromatic aldehydes using trichloroacetic acid or ceric sulfate as heterogeneous catalysts in excellent yields and short reaction times have ...

Different procedures for the syntheses of the title compounds were investigated. The best method for the preparation of the title compounds were the reaction of the readily available 2-formyL-1-methyl-5-nitroimidazole2- substituted-4-formylthiazoles with alkyl acetoacetate and alkyl aminocrotonate in boiling alcohol.

In recent years, the effects of heterogeneous catalysts for the oxidation of organic and inorganic pollutants in industrial wastewaters are spread. Traditionally, these reactions are usually carried out using suspensions of photo-catalysts such as TiO2. A chemical method including TiCl4, Al(NO3)3, ethanol amine, ethyl acetoacetate and aqueous ammonia were used for the fabrication of TiO2-Al2O3 ...

     Cellulose was applied as a reusable and green catalyst for the facile four-component synthesis of 6-amino-4-aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives using hydrazine monohydrate, ethyl acetoacetate, malononitrile and aryl aldehydes, under solvent-free and thermal conditions. The use of non-toxic and inexpensive catalyst, short reaction time, clean w...