Synthesis, structural characterization, crystallographic analysis and antibacterial properties of some nitrofuryl triazolo[3,4-b]-1,3,4-thiadiazines

A series of 1-(5-nitro-2-furyl)-2-bromo-3-aryl-2-propen-1-ones has been prepared through dehydrobromination of 2,3-dibromo-1-(5-nitro-2-furyl)-3-arylpropan-1-ones. Condensation of 1-(5-nitro-2-furyl)-2-bromo-3-aryl-2-propen-1-ones with 4-amino-5-mercapto-1,2,4-triazoles afforded a new class of 6-(5-nitro-2-furyl)-7-arylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines. The structure of the condensation products are fully confirmed by analytical, IR, NMR and mass spectral data. The formation of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines rather than 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines in the above condensation has also been confirmed by X-ray crystallographic analysis. The newly synthesized compounds have been screened for their in vitro antibacterial activity against Gram-positive and Gram-negative bacteria.