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.     

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.     

4-Functionally Substituted 3-Heterylpyrazoles: VII. 3-Aryl(heteryl)-1-phenyl-4-pyrazolecarbonyl Isothiocyanates

3-Aryl(heteryl)-1-phenyl-4-pyrazolecarbonyl isothiocyanates were synthesized by treatment of 3-aryl(heteryl)-1-phenyl-4-pyrazolecarbonyl chlorides with lead, sodium, or ammonium thiocyanate. Their reactions with amines, hydrazines, and acylhydrazines gave the corresponding thioureas and thiosemi- carbazides.     

4-Functionally Substituted 3-Heterylpyrazoles: IV. Benzylamino[3-aryl(heteryl)-4-pyrazolyl]methylphosphonic Acids

Derivatives of N-benzyl[3-aryl(heteryl)-4-pyrazolyl]methanimines react with diethyl phosphite to afford diethyl benzylamino[3-aryl(heteryl)-4-pyrazolyl]-4-methylphosphonates that on hydrolysis with 18% hydrochloric acid yield the corresponding aminophosphonic acids.     

4-Functionally Substituted 3-Heterylpyrazoles: III. 3-Aryl(heteryl)pyrazole-4-carboxylic Acids and Their Derivatives

3-Aryl(heteryl)-4-formylpyrazoles were cleanly oxidized by potassium permanganate in water-pyridine medium to afford in high yield 3-aryl(heteryl)pyrazole-4-carboxylic acids, that were further converted into the corresponding chlorides and amides.     

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.     

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.     

4-Functionally Substituted 3-Heterylpyrazoles: IV. 1-Phenyl-3-aryl(heteryl)-5-(4-pyrazolyl)-2-pyrazolines

3-Aryl(heteryl)-4-formylpyrazoles in condensation with methyl aryl(heteryl) ketones afforded 1-aryl(heteryl)-3-[3-aryl(heteryl)-4-pyrazolyl]propenones. The latter reacted with phenylhydrazine yielding 1-phenyl-3-aryl(heteryl)-5-(4-pyrazolyl)-2-pyrazolines.     

Synthesis and tautomerism of 2-[3(5)-aryl(methyl)pyrazol-4-yl]-1-benzimidazoles

An efficient method has been developed for the synthesis of 2-[3(5)-aryl(methyl)pyrazol-4-yl]-1H-benzimidazoles by cyclocondensation of 2-acylmethyl-1H-benzimidazoles benzoylhydrazones with DMF dimethylacetal. The tautomerism of the compounds obtained via migrations of a proton between the pyrazole nitrogen atoms has been studied by ¹H NMR. The more stable tautomers have electron acceptor aryl substituents placed at position 3 of the pyrazole ring and electron donor aryl substituents or a methyl at position 5. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1370–1377, September, 2006.     

4-functionally substituted 3-hetarylpyrazoles: XX. Synthesis of derivatives of 5-(pyrasol-4-yl)-1,2,4-triazole and 3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c][1,4]oxazine

N-Methylimines of 3-aryl-1-phenylpyrazole-4-carbaldehyde react with ethyl 2-aryl-hydrazino-2-chloroacetate with the formation of ethyl 1-aryl-5-(pyrazole-4-yl)-4,5-dihydro-1H-1,2,4-triazolecarboxylates. Analogous reactions of pyrazol-4-carbaldehyde N-(2-hydroxy)ethylimines results in derivatives of 3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c][1,4]-oxazines.     

Nitrilimine cycloaddition to 4-(pyrazol-5-yl)carbonyl-2-azetidinone and 4-(pyrazol-4-yl)carbonyl-2-azetidinone

The higly stereoselective nitrilimine cycloaddition onto the novel 3(R*)-phenyl-4(S*)-cinnamoyl-2-azetidinone 2 gave 4-(4,5-dihydropyrazol-5-yl)carbonyl-2-azetidinone 5 as the major product and 4-(4,5-dihydropyrazol-4-yl)carbonyl-2-azetidinone 6 as the minor one. Ceric ammonium nitrate (CAN) oxidation of the cycloadducts gave the title compounds with good overall yield.     

Synthesis of 4-(pyrazol-5-yl)-1,2,4-triazole-3-thiones

Condensation of pyrazolyl isothiocyanates 2 with N-substituted hydrazines provided the 2-methyl/phenyl-4-(pyrazol-5-yl)thiosemicarbazides 3 . Cyclization of 3 with formic acid-acetic anhydride or with triethyl orthoacetate-acetic anhydride provided 4-(pyrazol-5-yl)-l,2,4-triazole-3-thiones 4a-f and 5-methyl-4-(pyrazol-5-yl)-1,2,4-triazole-3-thiones 4g-I respectively.     

Synthesis of new 4-(pyrimidin-4-yl)pyrazol-3-one derivatives

1. Download high-res image (52KB)
2. Download full-size image

     

Functionally Substituted 3-Heterylpyrazoles: X. Reaction of 3-Aryl-1-phenyl-4-pyrazolecarbonyl Isothiocyanates with 3-Amino-5-methylisoxazole

3-Aryl-1-phenyl-4-pyrazolecarbonyl isothiocyanates react with 3-amino-5-methylisoxazole to afford 3-aryl-N-(3-acetonyl-1,2,4-thiadizol-5-yl)-1-phenylpyrazole-4-carboxamides.     

Synthesis of 5-Aryl(heteryl)-1-hydroxyethyl-4-(furyl-2-carbonyl)-3-hydroxy-3-pyrroline-2-ones

5-Aryl(heteryl)-1-hydroxyethyl-4-(furyl-2-carbonyl)-3-hydroxy-3-pyrroline-2-ones were synthesized via reactions of methyl ester of furyl-2-carbonylpyruvic acid with a mixture of aromatic or heterocyclic aldehyde and ethanolamine in dioxane. Antibacterial and antifungal activities of the synthesized compounds was studied.     

Synthesis and Structure of (2E)-3-Aryl(hetaryl)-2-[5-bromo-4-aryl(hetaryl)-1,3-thiazol-2-yl]acrylonitriles

Russian Journal of General Chemistry - Bromination of (2E)-3-aryl(hetaryl)-2-[4-aryl(hetaryl)-1,3-thiazol-2-yl]acrylonitriles proceeds regioselectively at the C5 atom of the thiazole ring with the...