“Push–pull” 2-ferrocenyl-4-hydroxythiazoles: A novel method of the construction of the thiazole ring

The title compounds were obtained by cyclization of ferrocenyl thioimidates in the presence of sodium ethoxide. They were transformed into the corresponding 4-acetoxy-derivatives in reaction with acetic anhydride/pyridine. The structure of 4-acetoxy-5-(ethoxycarbonyl)-2-ferrocenylthiazole was determined by X-ray diffraction. The EFISH measurements revealed significant second-order nonlinear properties of 4-acetoxy-2-ferrocenyl-5-(4-nitrophenyl)ferrocenylthiazole (μβ = 250 × 10−48 esu at 1907 nm).