An efficient iminophosphorane-mediated synthesis, NMR-IR spectroscopic andX-ray study of novel ferrocenylimidazole derivatives Part 10. Study on ferrocenes

Starting from ethyl beta -ferrocenyl-alpha -azidoacrylate (2), a series of novel 4-ferrocenylidene-1-aminoimidazolones (6a-j) was prepared in a pathwa y involving an aza-Wittig reaction followed by condensation of the resultin g carbodiimidoester with hydrazines. Formation of [1,2,4]triazines of type 7 was not observed. Simultaneously with the formation of 2, an interesting transformation was also observed to afford a novel imidazolone derivative ( 3) containing two ferrocenyl groups. The structures of the products were de termined by IR, H-1- and C-13-NMR spectroscopy (including 2D-COSY, DEPT, 2D -HMQC, and 2D-HMBC measurements), and in the case of compound 3 also by sin gle-crystal X-ray analysis. (C) 2001 Published by Elsevier Science B.V.