4-Functionally-substituted 3-heterylpyrazoles: XIX. 3-aryl-4-(5-isoxazolyl)pyrazoles

Oximes of 4-(4-pyrazolyl)-3-buten-2-onees obtained by successive reaction of 3-aryl-4-formylpyrazoles with acetone and hydroxylamine at the treatment with iodine suffered an oxidative cyclization yielding 3-aryl-4-(5-isoxazolyl)pyrazoles.     

Functionally Substituted 3-Heterylpyrazoles: IX. 3-Aryl(heteryl)-4-mercapto(thiocyanato,isothiocyanato)methylpyrazoles

By reaction of 3-aryl(heteryl)-4-chloromethylpyrazoles with thiourea and sodium thiocyanate respectively 3-aryl(heteryl)-4-mercaptomethylpyrazoles and 3-aryl(heteryl)-thiocyanatomethylpyrazoles were obtained. The latter were subjected to thermal isomerization into 3-aryl(heteryl)-isothiocyanatomethylpyrazoles.     

Polyfunctional pyrazoles. 4. Synthesis of 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]acrylic and-propionic acids

3-(3-Aryl-4-formyl-1-pyrazolyl)propionic acids are converted by Knoevenagel condensation under conditions of microwave activation into 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]acrylic acids. Reduction of the latter with hydrazine hydrate in the presence of Raney nickel gives 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]propionic acids. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 686–690, May, 2006.     

Functionally Substituted 3-Heterylpyrazoles: XI. 3-[3-Aryl(heteryl)pyrazol-4-yl]propenoic and Propanoic acids

3-Aryl(heteryl)-4-formylpyrazoles by condensation with malonic acid furnish 3-[3-aryl(heteryl)- pyrazol-4-yl]propenoic acids that in the presence of Raney nickel are reduced by hydrazine hydrate to 3-[3-aryl(heteryl)pyrazol-4-yl]propanoic acids. The successive conversion of both type acids into the corresponding acyl chlorides, esters, and amides was performed.     

4-Functionally Substituted 3-Heterylpyrazoles: XIII. 3-Aryl(heteryl)-4-(4-pyrazolyl)-1,2,3,4-tetrahydropyrimidin-2-ones(thiones)

Cyclocondesation of 3-aryl(heteryl)pyrazole-4-carbaldehydes with ethyl acetoacetate and urea (thiourea) in the presence of FeCl₃ · 6H₂O afforded 3-aryl(heteryl)-4-(4-pyrazolyl)-1,2,3,4-tetrahydropyrimidin-2-ones(thiones).__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 97–98.Original Russian Text Copyright © 2005 by Bratenko, Chornous, Vovk.     

Polyfunctional pyrazoles 5*. preparative synthesis of 1-aryl-4-formylpyrazole- 3-carboxylic acids

Treatment of methyl pyruvate N-arylhydrazones with the Vilsmeier-Haack reagent gave methyl 1-aryl-4-formylpyrazole-3-carboxylates, basic hydrolysis of which yielded the corresponding acids.     

4-Functionally-substituted 3-Heterylpyrazoles: XV. 3-Aryl(heteryl)-1-phenyl-4-pyrazolylmethylamines and Heterocumulenes Obtained Therefrom

By reduction of 3-aryl(heteryl)-1-phenyl-4-azidomethyl-pyrazoles in the presence of Raney nickel or by hydrazinolysis of N-[3-aryl(heteryl)-1-phenyl-4-pyrazolylmethyl]phthalimides 4-pyrazolylmethylamines were obtained that in reaction with bis(trichloromethyl) carbonate afforded 3-aryl-(heteryl)-1-phenyl-4-pyrazolylmethyl isocyanates, and with carbon disulfide furnished 3-aryl-(heteryl)-1-phenyl-4-pyrazolylmethyl isothiocyanates.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 247–251.Original Russian Text Copyright © 2005 by Bratenko, Panimarchuk, Mel’nichenko, Vovk.     

Polyfunctional imidazoles: I. Synthesis of 1-substituted 4-chloro-1<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carbaldehydes by Vilsmeier-Haack reaction

2-[Alkyl(aryl)amino]acetamides in reaction with Vilsmeier-Haack reagent afforded 1-alkyl(aryl)-4-chloro-1H-imidazole-5-carbaldehydes.     

4-Functionally Substituted 3-Heterylpyrazoles: VIII. 3-Aryl(heteryl)-4-hydroxyl(chloro)methylpyrazoles

3-Aryl(heteryl)pyrazole-4-carbaldehydes were reduced with sodium tetrahydridoborate under mild conditions to give 3-aryl(heteryl)-4-hydroxymethylpyrazoles which were converted into the corresponding 4-chloromethyl derivatives by treatment with thionyl chloride. The subsequent reaction with triphenylphos- phine led to formation of triphenyl(4-pyrazolylmethyl)phosphonium chlorides, and Wittig reaction of the latter with aromatic or heteroaromatic aldehydes yielded 4-[2-aryl(heteryl)ethenyl]pyrazoles.