Synthesis of heterocyclic compounds which have biological activity

Isothiocyanates have been used as synthetic intermediates to prepare biologically activeheterocyclic compounds. It is possible to obtain the heterocycles such as thiazoles, thiazolinesand thiazolidines containing N-C-S bonds by this reagent. These sulfur heterocycles exhibitvarious biological and physicological activities such as pesticidal, nematocidal, herbicidal,bactericidal and anti-cancer.On the other hand, pyrazoline-5-one derivatives are an important class of heterocycliccompounds with wide scientific and technical application as materials in catalysis andpotential antitumor medications.This study planned to synthesize new heterocycles having possible biological activities. In thefirst step, 1-methyl-3-phenyl-1,4-dihydropyrazol-5-one having active methylene group as thestarting materials were prepared. This compound was reacted with phenyl isothiocyanate inbasic medium and carbothioic acid phenylamide (2) compound was obtained. Then, theirring closure reactions were prepared by phenacyl bromide and oxalyl chloride. In the secondstep, 1-methyl-3-phenyl-1,4-dihydropyrazol-5-ones compounds were reacted with differentaldehydes to give benzylidene derivatives . In the last step, structure determinations of all newcompounds were identificated by FTIR and 1H NMR spectroscopic data.Key Words: Phenyl isothiocyanate, pyrazoline-5-one, benzylidene derivatives, biologicalactivity.