Diferrocenyl(areno)oxazoles, spiro(arenooxazole)cyclopropenes, quinolines and areno[1,4-]oxazines: Synthesis, characterization and study of their antitumor activity

A novel 2-(Z,E-1,2-diferrocenylvinyl)arenooxazoles 4a-f and 5a-e (24–32%, 2:1, respectively), 3-ferrocenyl-2-ferrocenylmethyl-2-morpholino-2H-areno[1,4]oxazines 7a-f (22–33%), 2′,3′-diferrocenyl-3H-spiro[areno[d]oxazole-2,1′-cycloprop[2]ene] 6-f (5–6%), 2-ferrocenylarenooxazoles 3a-e (4–6%), and 3,4-diferrocenyl-8-hydroxyquinolines 8d-f (ca ∼25–30%) are described by reactions of 2,3-diferrocenyl-1-morpholino-cyclopropenium salts 1 with 1,2-aminophenols 2a-e and 2,3-aminonaphthol 2f in the presence of Et3N is described. A new reaction of transformation of the intermediate products of the addition of 1,2-aminoarenols 2a-f to the diferrocenyl-cyclopropenium cation 1 in the positions C(1) and C(2) is found. The characterization of the new compounds was done by IR, 1H- and 13C-NMR spectroscopy, mass-spectrometry, elemental analysis, and X-ray diffraction. Compounds 4a, 4e, 5a, 5e and 6a were the most active with modest cytotoxic activity against three human cancer cell lines K-562 (leukemia), MCF-7 (breast) and SKLU-1 (lung).