Synthesis of novel 1-[1H-indol-3-yl] phthalazine-4- derivatives with expected antimicrobial activity

ABSTRACT

Ethyl 2- [1-[1H-indol-3-yl] phthalazin-4- yloxy] acetate [2] condensed with some aromatic amines and hydrazine hydrate to give the corresponding amides [3a-c] and hydrazide [4] derivatives, respectively. The key intermediate compound [4] was subjected to various reactions to yield the oxadiazoles [5] and [10], triazole [7], thiazolidinone [12] and pyrazole [13] derivatives. Also, the key intermediate thiol derivative [14] was subjected to alkylation reaction to give 15,21 and 22 and to acetylation to yield compound [16]. The latter compound condensed with p- anisaldehyde to yield the alpha, beta unsaturated keto compound [17] which in turn was condensed with hydrazine hydrate to yield pyrazoline [18] and with hydroxyl amine to give the isoxazoline [20]. The antimicrobial activity for some representative samples of the new prepared compounds was studied. The data showed that some of the tested compounds possess moderate activity towards G-positive G-negative bacteria and fungi compared with the reference drugs Ampicillin and Mycostatin. Also, the MIC of these compounds showed activity in the range of 125-250 microg/disk Compared with the reference drugs