Synthesis of novel scaffolds based on bis-thiazole or bis-triazolothiadiazine linked to quinoxaline as new hybrid molecules

Abstract

A synthesis of novel bis-thiazoles, linked to quinoxaline as novel hybrid molecules, was accomplished in good yields by the reaction of the appropriate α-haloketones or α-keto-hydrazonoyl chlorides with the corresponding bis(hydrazinecarbothioamide) in ethanol/dimethylformamide (EtOH/DMF) at reflux in the presence of a few drops of triethylamine (TEA). The reaction of the appropriate thioamide with the corresponding bis(2-bromoethanone) yielded novel bis-thiazoles. Furthermore, by reacting bis(2-bromoethanone) with the appropriate 4-amino-3-mercapto-1,2,4-triazole derivatives, novel bis(5,6-dihydro-s-triazolo[3,4-b]thiadiazines) linked to quinoxaline moiety were obtained in good yields. The starting bis-thiosemicarbazone was obtained by reacting 1,1'-((quinoxaline-2,3-diylbis(oxy))bis(4,1-phenylene))diethanone with thiosemicarbazide in EtOH containing a few drops of acetic acid (AcOH) at reflux. On the other hand, the 1,1'-((quinoxaline-2,3-diylbis(oxy))bis(4,1-phenylene))bis(2-bromoethanone) was obtained from the corresponding bis(acetyl) derivative upon treatment with N-bromosuccinimide (NBS) in the presence of p-toluenesulfonic acid (p-TsOH), respectively. Structures of new compounds were confirmed using elemental analyses and spectral data. </p