Synthesis, spectroscopic studies and characterizations of some new bis thiosemicarbazones and their cyclization reactions

Abstract

The reaction of trans-1,4-dichloro-2-butene 1 with selected phenols affords (E)-1,4-bis(aryloxy)-2-butenes 2a-d which are converted into bis-thiosemicarbazones 3a-h via the reactions with thiosemicarbazide and 4-methyl thiosemicarbazide, respectively. Similarly, 4-methyl-5-ethoxycarbonyl-2,3-dihydro-1,3-thiazoles 4a-h are synthesized via the reaction of bisthiosemicarbazones 3a-h with ethyl 2-chloroacetoacetate. trans-1,4-Dithiocyanato-2-butene 5 is obtained from the reaction of KSCN and trans-1,4-dichloro-2-butene 1. Furthermore, the bis-2-amino-1,3,4-thiadiazoles 6k and l are obtained from the reaction of trans-1,4-dithiocyanato-2-butene 5 with thiosemicarbazide and 4-methyl thiosemicarbazide, respectively. These compounds are characterized by elemental analyses, infrared, 1 H-, 13 C-NMR and mass spectrometry. Finally, the microbial features of all compounds are determined. Some of them exhibited microbial activities at low level, and the electronic absorption spectra of the compounds 3b,d,f and h are measured in organic solvents (MeOH, DMF, DMSO and 1,4-dioxane) with various polarities.