The syntheses of 2-[5-oxso-4-(substituted phenylazo)-2,5-dihydro-2H-pyrazol-3-ylazo]-indan-1,3-diones and investigation of electronic spectra of the compounds

Diazonium salts were prepared with the use o-, m-, p-substituted anilines and cyano-(substituted phenylazo)-acetic acid ethyl ester was prepared by the coupling reaction of diazonium salts with ethyl cyanoacetate and finally 5-Amino-4-(substituted phenylazo)-1H-pyrazol-3-ol was obtained by the ring close of this compound with hydrazinemonohydrate. The diazonium salts of these compounds were prepared again and 2-[5-oxo-4-(substituted phenylazo)-2,5-dihydro-1H-pyrazol-3-ylazo]-indan-1,3-diones was prepared by thecoupling of 1,3-indandione at 2-positinon. The structures of the products synthesized were elucidated by 1H-NMR, MS and FT-IR spectrum. Also the behavior of the compounds with the solvent, concentration and acid-base was investigated with the use of UV-visible spectroscopy.