MICROWAVE ASSISTED RAPID AND EFFICIENT SYNTHESIS OF 3-[5-(ARYL)-3,4-DIHYDRO-2H-PYRAZOL-3-YL]-6-SUBSTITUTED CHROMEN-4-ONE WITH THEIR ANTIMICROBIAL ACTIVITY

A. Zechariah Jebakumar
Dept. of Research and Scientific studies, Prince Sultan Military college of Health Sciences, Dhahran-31932, Kingdom of Saudi Arabia.
Hassan S. Nondo
Dept. of Research and Scientific studies, Prince Sultan Military college of Health Sciences, Dhahran-31932, Kingdom of Saudi Arabia.
Siju K. George
Dept. of Research and Scientific studies, Prince Sultan Military college of Health Sciences, Dhahran-31932, Kingdom of Saudi Arabia.
G.Manoj
Dept of Pharmacology, C.L. Baid Metha College of Pharmacy, Thoraipakkam, Chennai - 600096, India

Antidiarrhoeal activity ,Randia uliginosa ,Traditional medicine ,Castor oil induced diarrhoea ,Enteropooling method ,

The conventional method for the preparation of title compounds are reported earlier. It involved the preparation of substituted chromones by Vilsmear-Haack reaction. Formylation of 2-hydroxy ketone in presence of DMF-POCl3 afforded chromones. The condensation of substituted chromones and aromatic ketones in presence of sodium hydroxide and alcoholic medium resulted in the formation of substituted chalcones. Chalcones on further reaction with hydrazine hydrate in alcoholic medium gave pyrazolines. Pyrazolines gave its acetyl derivative by the reaction with sodium acetate and acetic anhydride.The synthesis of pyrazoline involving conventional method took 2 hrs for completion of reaction and yield were in the range of 60-70%. The same reaction when performed under microwave assisted condition took only 1-1½ minutes for completion and yield were also improved to 80-85%. The structures of these compounds were confirmed on the basis of their spectral data. All the newly synthesized compounds have been screened for their antimicrobial activity against gram positive and gram negative microorganisms.

7 , 1 , 2017