Synthesis of new pyrazole derivatives derived from 4-hydroxy
coumarin and evaluation of their biological activity
In this work new coumarin derivatives were synthesized, from 4-hydroxy
coumarin as a starting material, by its reaction with acetyl chloride, using pyridine
as a base to form 3-acetyl-4-hydroxy coumarin 2
Then the reaction was followed
up by the formation of schiff bases 3-7, through the treatment of 2 and hydrazine
derivatives in boiling absolute ethanol.
Pyrazole derivatives 8-12 were finally
synthesized by ring closure reaction of schiff bases in the presence of few drops of
concentrated sulfuric acid as a catalyst