Thermal Condensation of 1-Aryl/ hetaryl-3-methyl-2- pyrazolin-5-ones with Aromatic Aldehydes. synthesis of 4- arylidenepyrazolones

Heating of 3-methyl-1-(pyrid-2-yl / 4-chlorophenyl)-2-pyrazolin-5-ones (1) and some aromatic aldehydes at 150 – 160 oCaffords the corresponding 4-arylidene-2-pyrazolin-5-ones (2) ascolored products with high yields. These new products werecharacterized by UV-vis, FT-IR and 1H NMR spectro scopictechniques and elemental analysis.