Synthesis and antifungal activity of novel 3,6‐diaryl‐5H‐[1,2,4]triazolo[4,3‐b][1,2,4]triazepines

5‐Aryl‐3,4‐diamino‐1,2,4‐triazoles 5 on treatment with β‐chlorocinnamaldehydes 7 in the presence of catalytic amount of p‐TsOH and N,N‐dimethylformamide as an energy transfer medium under microwave irradiation and as solvent with oil‐bath heating at 80 °C affords novel 3,6‐diaryl‐5H‐[1,2,4]triazolo[4,3‐b]‐1,2,4]triazepines 8 . The structures of the synthesized compounds were established on the basis of ¹H NMR, IR, mass spectral data and elemental analysis.     

A convenient synthesis and biological activities of novel 6‐aryl‐3‐(1,2,3,4‐tetrahydroxybutan‐1‐yl)‐7H‐1,2,4‐triazolo‐[3,4‐b][1,3,4]thiadiazines

A series of novel 6‐aryl‐3‐(1,2,3,4‐tetrahydroxybutanol‐1‐yl)‐7H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazines were easily synthesized in high yields by means of the reactions of 4‐amino‐5‐(1,2,3,4‐tetrahydroxybutyl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione ( 1 ) with substituted ω‐bromoacetophenones or ω‐chloroacetophenone. Nearly all of the title compounds possess plant growth‐promoting activities.     

A new convenient synthesis of 2,4‐disubstituted‐1,2,4‐triazolo[1,5‐a] quinazolin‐5(4H)‐ones

A novel series of 2,4‐disubstituted‐1,2,4‐triazolo[1,5‐a]quinazolin‐5(4H)‐ones were prepared by Dimroth rearrangement of their respective isomers namely 1,4‐disubstituted‐[1,2,4]triazolo[4,3‐a]‐quinazolin‐5(4H)‐ones. The latter were prepared via new synthetic strategy based on 1,5‐elecrocyclization of the respective N‐(4‐oxo‐3‐phenylquinazolin‐2‐yl)nitrilimines.