CuI Promoted Efficient Synthesis and Antimicrobial Activity of Substituted 8,8-Dimethyl-5-phenyl-2-(pyrazin-2-yl)-5,7,8,9-tetrahydro-6H-[1,3,4]thiadiazolo[2,3-b]quinazolin-6-one

In present study, an efficient synthesis of substituted 5,7,8,9-tetrahydro-6H-[1,3,4]thiadiazolo[2,3-b]quinazolin-6-one compounds promoted by CuI as catalyst was carried out. These derivatives were obtained from 1,3,4-thiadiazol-2-amine, dimedone and substituted aromatic aldehyde in presence of CuI in ethanol as solvent at 70 ºC. Initially, 1,3,4-thiadiazol-2-amine was synthesized from pyrazine-3- carboxylic acid reacted with thiosemicarbazide in the presence of 50% H2SO4 in acetonitrile at 70 ºC. All the newly obtained derivatives  were evaluated by the spectroscopic techniques such as 1H NMR, 13C NMR and LCMS and structural determination of titled analogous  were analyzed by elemental analysis. The antibacterial activities of the newly synthesized compounds were also screened.