Synthesis and antibacterial activity of some new thiazole and thiophene derivatives

Dibenzobarrelene 1 was reacted with cyanoacetic acid hydrazide and thiosemicarbazide to give the corresponding 3-oxo-propiononitrile and thioamide derivatives 2 and 16, respectively. The base-catalyzed reaction 3-oxo-propiononitrile derivative 2 with phenyl isothiocyanate yielded the non-isolable intermediate 3. Treatment of 3 with dilute HCl afforded the corresponding thiocarbamoyl derivative 4. The intermediate 3, thiocarbamoyl 4 and thioamide derivatives 16 were utilized as key intermediates for the synthesis of some new thiazole 5, 6a, 6b, 7, 8, 10a, 10b, 12, 14a, 15, 17a, 17b, and 18; and thiophene 13a–d derivatives, respectively. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral studies. Representative compounds of the synthesized product were tested and evaluated as antibacterial agent.

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