Hansa Parekh

Synthesis and biological evaluation of chalcones and acetyl pyrazoline derivatives comprising furan nucleus as an antitubercular agents

A series of 1-{5-[5-(m,p-dichlorophenyl)furan-2-yl]-3-aryl-4,5-dihydro-1H-pyrazol-1-yl} ethanone (3a–k) have been synthesized by the condensation of (2E)-3-[5-(m,p-dichlorophenyl)furan-2-yl]-1-arylprop-2-en-1-one (2a–k) with hydrazine hydrate in glacial acetic acid. The synthesized compounds have been characterized on the basis of elemental analyses and spectral studies. All the synthesized products have been screened for their antibacterial, antifungal, and antitubercular activity.

SYNTHESIS AND BIOLOGICAL EVALUATION OF NOVEL OXADIAZOLE AND ARYLACETAMIDE DERIVATIVES

1,3,4-Oxadiazoles of the type 2a-o have been prepared by the condensat ion of p-acetamidophenoxyacetyl hydrazide T_ w i th dif ferent aromatic acids. The same hydrazide _7 on t rea tment w i t h aromatic acid chlorides afforded subst i tuted arylacetamides of the type 3a-o. The structure of the compounds synthesised have been assigned using elemental analyses, IR and PMR spectral studies. The pharmacological profile of the compounds synthesised is described. Some of the synthesised compounds showed moderate in vitro ant imycobacterial act ivi ty against a strain of Mycobacterium tuberculosis H37 Rv. INTRODUCTION In the past years, considerable evidence has been accumulated to demonstrate the ef f icacy of 1 ,3 ,4-oxad iazo le (1-4) and ary lacetamide (5-9) der ivat ives as b io logical ly act ive compounds. Moreover , acetaminophen and some of its derivatives are useful for aspirin allergic individuals (10). The newer and less hepatotoxic agents may be developed bearing paracetamol moiety. Led by these considerations and by our interest in therapeutically act ive compounds , it appeared of interest to synthesise some novel oxadiazole and arylacetamide derivatives and assess their pharmacological profile. The reaction of p-acetamidophenol w i th ethyl chloroacetate in the presence of dry acetone and anhyd. K ^ C O ^ gave the desired ethyl p-acetamidophenoxy acetate wh ich was converted into p-acetamidophenoxyacety l hydrazide 1_ by t reatment w i th a slight excess of hydrazine hydrate in absolute ethanol under ref lux. The hydrazide ]_ on cyc l isat ion w i t h various aromatic acids in presence of POCI^ afforded corresponding 2-p-acetamido phenoxymethy l -5 ary l -1 ,3 ,4-oxad iazo les 2a-o. The same hydrazide 1_ was t reated w i t h di f ferent aromatic acid 1 2 chlorides in presence of pyridine to yield corresponding Ν -aroyl, Ν -p-acetamidophenoxyacyl hydrazines 3a-o (scheme). The structure of the compounds synthesised have been assessed on the basis of elemental analyses, IR, and PMR spectral data. The compounds were evaluated for their antimicrobial screening against Gram -ι-ve, Gram -ve bacterial and fungal strain. Some of the compounds were evaluated for their in vitro antimycobacterial activity towards a strain of Mycobacterium tuberculosis H37 Rv. Vol. 3, No. 6, 1997 Synthesis and Biological Evaluation of Novel Oxadiazole and Arylacetamide Derivatives SCHEME H g C C H N ^ y— OH + C I C H 2 C O O C 2 H 5 V anhyd . K2CC>3 Acetone Ο HgC C HN y O C H 2 C O O C 2 H 5 ο n h 2 N H 2 • H 2 0 ψ Absolute ethanol Ο HgC C HN y O C H 2 C N H N H 2