合成路线1

Friedel Crafts acylation of methyl 2-methylazulene-1-carboxylate (I) with benzoyl chloride (II) and AlCl3 yielded the benzoylazulene (III). Subsequent saponification of the ester function with NaOH, followed by decarboxylation of the resulting acid (IV) using p-TsOH in boiling benzene provided (V). Mannich reaction of (V) with bis(dimethylamino)methane and paraformaldehyde produced amine (VI), which was quaternized with MeI to furnish the ammonium salt (VII). This was displaced by ethanolic KCN to give nitrile (VIII). Thioamide (IX) was then obtained by reaction of (VIII) with thioacetamide and HCl. Finally, the thiazole ring was constructed by cyclization of (IX) with bromoacetone.