Synthesis of some novel 3-(2-chloro-3-quinolyl)-5-phenyl [1,3] thiazolo [2,3-c] [1,2,4] triazoles

Various acetanilides (1) were treated with DMF and POCl3 complex (Vilsmeier's reagent) to obtain 2-chloro-3-quinolinecarboxaldehydes (2). The latter on condensation with thiosemi- carbazide in alcohol gave the corresponding thiosemicarbazones (3), which on treatment with substituted phenacyl bromides (4) in alchol gave quinoline substituted thiazoles (5). The dehydrogenative cyclisation of 5 was achieved with chloranil in refluxing toluene resulting in novel 3-(2-chloro-3-quinolyl)-6-phenyl [1,3] thiazolo [2,3-c] [1,2,4] triazoles (6) whose structures are supported by spectral data.