The N-heterocyclic carbene (NHC)-organocatalyzed enantioselective annulation reaction of pyrazolones with α,β-unsaturated aldehydes proceeding via the chiral α,β-unsaturated acyl azolium intermediates under oxidative conditions is presented. The reaction afforded dihydropyranone-fused pyrazoles in moderate to good yields and good er values under operationally simple and base-free conditions.

abstarct:a simple one-pot synthesis of pyrano[ 2,3-c]pyrazoles was developed by a three-component reaction of various benzaldehydes, malononitrile and 1-phenyl or hydro-3-methyl-1h-pyrazol-5(4h)-one in the presence of n-methyl pyridinium p-toluene sulfonate (nmpyts) as a catalyst. all of the synthesized compounds were identified by ir, 1h nmr, 13c nmr and mass spectroscopy techniques. in the me...

A series of 1-phenyl-3-aryl-5-(4-(2-ethanoloxy) phenyl)-1H-pyrazoles were synthesized from chalcones and studied for their in vitro antibacterial activity. Chalcones i.e.,1-aryl-3-(4hydroxyphenyl) prop-2-en-1-ones, 1 on reaction with phenyl hydrazine yielded the corresponding 1-phenyl-3-aryl-5-(4-hydroxyphenyl)-1H-pyrazoles 2 which on further reaction with 3-chloroethanol furnished the title co...

The inhibitive effect of compound (1-acetyl-4, 5-dihydro-5-Bromophenyl-3-(thiophen-2yl) pyrazoles) on mild steel in 1M H2SO4 and 1M HCl was investigated by weight loss, Potentiodynamic polarization and electro chemical impidence studies. The synthesized compound of 1-acetyl-4, 5-dihydro-5-Bromophenyl-3-(thiophen-2yl) pyrazoles was characterized by FTIR, H NMR, C NMR and mass. The purity of the ...

A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I2/HIO3 gives the appropriate 4-iodopyrazol...

Synthesis of di-pyrrolyl-substituted pyrazoles (dpp) and anion binding studies in protonated form are reported. Dpp show [2 + 2] binding of trifluoroacetate in the solid state to afford nanometer- and micrometer-scale architectures.

Palladium-catalyzed amidation of five-membered heterocyclic bromides that contain multiple heteroatoms was achieved for the first time using the Pd/1 catalyst system. This system allows for efficient access to N-arylated imidazoles, pyrazoles, thiazoles, pyrroles, and thiophenes in moderate to excellent yield. Experimental results and DFT calculations point to the need for electron-rich and esp...

А para-chlorophenyl substituent was firstly obtained into the structure of pyridyl-substituted 4-nitrosopyrazole by cyclocondensation hydrazine hydrate with corresponding isonitroso-β-dicarbonyl compounds. The previously unknown 3(5)-(4-chlorophenyl)-5(3)-pyridine-(3(4))-yl-4-nitroso-1H-pyrazoles and 3(5)-alkyl(aryl)-5(3)-pyridine-(3(4))-yl-4-nitroso-1H-pyrazoles is proved studied in detail mod...

Ethyl diazoacetate (EDA), which is easily prepared from ethyl glycinate and NaNO2, reacts in situ with alkynes a water micelle environment without organic solvent to form pyrazoles. The reaction pH dependent, as the presence of protic catalysis (H2SO4 4 %, 3.5) mixture 3,5- 4,5-disubstituted pyrazoles was obtained, while, at 5.5, only 3,5-disubstituted isomer obtained. surfactant TPGS-750-M cru...