Synthesis, Characteristics and Physico-chemical Study of Some Dichloro Pyrazoles

Abstract

Some new 3,5-Diaryl-1-substituted pyrazoles have been synthesized by the action of isonicotinic acid and thio-semicarbazide on 3-iodo flavanones in pyridine medium. 3-Iodo flavanones obtained from 2-hydroxy-3,5-dichloro chalcones and ICl in acetic acid. Structure of these compds. has been established by chem. and spectral anal. (NMR & IR). Purity of these heterocycles was checked by TLC. The interaction of Cu(II), Co(II) with 1-carboxamido-3-(2-hydroxy-3,5-dichloro phenyl)-5-(4-methoxy phenyl) pyrazole (L1), 1-thiocarbaxomedo-3(2-hydroxy-3,5-dichloro phenyl)-5-(4-methoxy phenyl) pyrazole (L2) have been carried out by employing Bjerrum-Calvin pH metric titrn. technique, at 27°C in 70% dioxane-water medium. The data obtained can be used for the detn. of proton ligand formation nos. (η). From the formation curve, the proton-ligand stability const. pK values have been evaluated using half integral method. The metal ligand formation nos. (η) are estd. by using Irving Rossotti's expression. Metal-Ligand stability consts. for 1:1 complex & 1:2 complex have been calcd. which are designated by letters log K1 & log K2 resp. [on SciFinder(R)]