Synthesis of new derivatives of pyrazole using three component reactions

Pyrazole is a five membered and two-nitrogen containing heterocyclic ring. These structures have been investigated in the development of novel compounds with hypoglycemic, analgesic, anti-inflammatory, antimicrobial, anticonvulsant, antidepressant, antimycobacterial, antioxidant, antiviral, insecticidal and antitumor activities. Therefore, these compounds have been synthesized as target structures by many researchers and were evaluated for their biological activities. It is believed that the bioactivity of pyrazole derivatives will be beneficial for the rational design of new generation of small molecule drugs [1]. Although pyrazoles have been intensely studied for over a century, there is still great demand for novel derivatives with enhanced or unusual medicinal activities to combat various diseases and pathophysiological conditions [2]. In the present study we wish to introduce an efficient three components reaction protocol for the catalyst free synthesis of pyrazole and derivatives by the reaction of 1,2-disulfonylhydrazides 1, dialkyl acetylenedicarboxylates 2 and isocyanides 3 at the room temperature (Scheme 1).