Ultrasound-promoted synthesis of novel fused heterocycles by criss-cross cycloaddition

This work reports a novel and highly efficient methodology for the synthesis of per-hydrotriazolotriazoledithions from two successive 1,3-dipolar cycloaddition under ultrasound irradiation. Aromatic 2,3-diazabuta-1,3-diene ligands with thiocyanates in glacial AcOH produced the corresponding perhydro [1,2,4] triazolo [1,2-a] [1,2,4] triazole-1,5-dithiones via criss-cross cycloaddition reactions under ultrasound irradiation. Structures of all compounds were characterized by H-1 and C-13 NMR, UV, IR and elemental analysis spectral data. The major advantages of the reported method are its selectivity, operational simplicity, extremely mild reaction conditions, short reaction times, and excellent yields. (C) 2012 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.