Synthesis and pharmacological screening of some novel naphtho [2,1-b] furo-pyrazolines, isoxazoles and isoxazolines

2-Acetylnaphtho [2,1-b]furan 1 was reacted with various aromatic aldehydes in presence of alkali, to produce corresponding chalcones 2a-i. These were converted into 1-phenyl-3-(naphtho[2,1-b]fur-2yl-5-aryl-2-pyrazolines 3a-i and 1-(4-nitrophenyl)-3-(naphtho[2,1-b]fur-2yl-5-aryl-2-pyrazolines 4a-i by treatment with phenyl hydrazine and 4-nitrophenyl hydrazine respectively. The reaction of chalcones 2a-i with hydroxyl amine hydrochloride in presence of sodium acetate in glacial acetic acid produced 3-(naphtho[2,1-b]fur-2yl)-5-aryl-2-isoxazoles 5a-i, whereas similar reaction in the presence of potassium hydroxide yielded 3-(naphtho[2,1-b]fur-2yl)-5-aryl-2-isoxazolines 6a and 6e. All the compounds have been characterized by elemental analysis and spectroscopic data. These novel biheterocyclic compounds have been screened for antibacterial, antifungal, anthelmintic and analgesic activities. The compound 4e showed promising antimicrobial activity, some of the compounds exhibited moderate antibacterial and antifungal activity. The only compound that showed maximum analgesic activity is 3d. Anthelmintic activity revealed the compounds 4e, 5b and 5i were as active as the standard drug.