Synthesis and antimicrobial activity evaluation of indole-azole-fluoroquinolone hybrids with highly functionalized functional groups

4-Amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-one (1) was converted to the corresponding Schiff base (2) by treatment with indole-3-carbaldehyde. The treatment of 4-aminoantipyrine with ethylbromoacetate, hydrazinhydrate and various iso (thio) cyanates, respectively, followed by cyclization reaction using basic reagent resulted in the formation of a second 1,2,4-triazole ring in the structure of final product. Quinolone containing Mannich bases were synthesized from 1,2,4-triazoles in the presence of formaldehyde (7a-h). All the newly synthesized compounds were screened for their antimicrobial activities. Most exhibited good to moderate antibacterial and/or antifungal activity. The structural assignments of the new compounds were based on elemental analysis and spectral (IR, 1 HNMR, 13 CNMR, and LC–MS) data.