title: Novel, mercury-free synthetic pathway for trifluoromethylthio-substituted metallocenes.
abstract: A novel synthetic pathway for trifluoromethylthioferrocene (3), which does not involve the use of toxic mercury(II)-based reagents, is described. The novel approach involves first the treatment of the commercially available bromoferrocene (1a) with NaSCN in the presence of copper(+I) to yield thiocyanatoferrocene (1), and then the reaction of 1 with the Rupper-Prakash reagent and tetrabutylammonium fluoride (TBAF) to give 3 in an overall yield of 60%. This approach could be extended for the preparation of thiocyanato-(4) and trifluoromethylthio-ruthenocene (7), which are herein both reported for the first time. Interestingly, diferrocenyl disulfide (2a) and diruthenocenyl disulfide (5) could be isolated as side-products during the synthesis of 3 and 7, respectively. All new compounds were unambiguously characterized by (1)H, (13)C, and (19)F NMR spectroscopy, mass spectrometry, cyclic voltammetry, elemental analysis, as well by X-ray crystallography for 1, 4, 4b, 5, 6, and 7. 1-7 were further tested for their toxic activity on cervical cancer (HeLa) and noncancerous (MRC-5) cell lines. All organometallic compounds were found either to be nontoxic or to have a moderate toxicity toward the cell lines used in this study.
authors.affiliation: Department of Chemistry and ‡Institute of Molecular Cancer Research, University of Zurich , Winterthurerstrasse190, CH-8057 Zurich, Switzerland.
authors.forename: Jeannine
authors.initials: J
authors.lastname: Hess
authors.forename: Sandro
authors.initials: S
authors.lastname: Konatschnig
authors.forename: Sandra
authors.initials: S
authors.lastname: Morard
authors.forename: Vanessa
authors.initials: V
authors.lastname: Pierroz
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferrari
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spingler
authors.forename: Gilles
authors.initials: G
authors.lastname: Gasser
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000633:toxicity; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018360:Crystallography, X-Ray; D006367:HeLa Cells; D006801:Humans; D008628:Mercury / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity
chemical_list: D000970:Antineoplastic Agents; D009942:Organometallic Compounds; C013108:metallocene; D008628:Mercury