title: An efficient and simple approach for the synthesis of pyranopyrazoles using imidazole (catalytic) in aqueous medium, and the vibrational spectroscopic studies on 6-amino-4-(4'-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole using density functional theory.
abstract: We describe a one-pot four component synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of an organocatalyst imidazole in water as medium. A plausible mechanism for the formation of imidazole catalyzed pyranopyrazoles has been envisaged. This method is rapid, simple, provides products in good yield, and is eco-friendly. In addition, based on the optimized geometry, the frequency and intensity of the vibrational bands of 6-amino-4-(4'-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole were obtained by the density functional theory (DFT) calculations using 6-31G(d,p) basis set. The vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement.
authors.affiliation: Department of Chemistry, Smt. V.H.D. Central Institute of Home Science, Bangalore 560001, India.
authors.forename: Aisha
authors.initials: A
authors.lastname: Siddekha
authors.forename: Aatika
authors.initials: A
authors.lastname: Nizam
authors.forename: M A
authors.initials: MA
authors.lastname: Pasha
mesh_terms: D002021:Buffers; D002384:Catalysis / Q000187:drug effects; D004526:Efficiency; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D011714:Pyrans / Q000138:chemical synthesis / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis / Q000379:methods; D013059:Spectrum Analysis, Raman; D014732:Vibration; D014867:Water / Q000494:pharmacology
chemical_list: D002021:Buffers; D007093:Imidazoles; D011714:Pyrans; D011720:Pyrazoles; D014867:Water; C029899:imidazole