Franck Le Bideau

A series of unconjugated ferrocenyl phenols: prospects as anticancer agents.

We recently reported that a ferrocenyl diphenol butene derivative showed a very strong cytotoxic effect on both hormone‐dependent and ‐independent breast cancer cell lines. In order to obtain more information about the structure–activity relationship in the cytotoxicity of small ferrocene compounds, we have prepared a series of simple unconjugated ferrocenyl diphenol complexes (ortho,para; meta,para; para,para). These compounds retain a reasonable to good affinity for both estrogen receptor types, with higher values for the β form, and superior binding for the para,para diphenol complex (RBA=28u2009%). In vitro these complexes exhibit significant cytotoxic effects on hormone‐independent prostate (PC3) and breast cancer cell lines (MDA‐MB231), with IC50 values between 2.5 and 4.1u2005μM. This effect is more marked with PC3, the ortho,para diphenol complex proving the most effective. On the hormone‐dependent MCF7 breast cancer cell line, the observed effect seems to be the result of two components, one cytotoxic (antiproliferative), the other estrogenic (proliferative). Electrochemical studies show that the cytotoxic effect of the complexes correlates with the ease of oxidation of the ferrocene group. All these complexes are much less cytotoxic than the ferrocenyl diphenol butene derivative.

New and efficient routes to biomolecules substituted with cyclopentadienyltricarbonylrhenium and -technetium derivatives.

The small, compact, robust, and nonpolar units of [CpM(CO)3] (M = Re, Tc) coupled with biomolecules may be considered as bioorganometallic entities of potential interest in the field of medicinal chemistry. However, the short half-life of useful radionuclides (186Re t1/2 = 3.7 d, 188Re t1/2 = 16.8 h, 99mTc t1/2 = 6 h), the risks inherent in their use, and their cost have led chemists to search for novel synthetic strategies that allow the rapid introduction of the [CpM(CO)3] moiety as a late step in the course of synthesizing the target molecule. The present paper describes different strategies recently reported in the literature to tackle this problem.

Evaluation of the carbonyl metallo immunoassay (CMIA) for the determination of traces of the herbicide atrazine

Abstract The non-isotopic immunoassay (CMIA) was investigated for the quantification of the herbicide atrazine. This assay combines transition metal carbonyl complex and Fourier transform infrared spectroscopy. We describe the synthesis of three dicobalt hexacarbonyl tracers, derivatives of atrazine. Their relative binding affinity towards two purified IgG fractions of polyclonal rabbit anti-sera (anti-atrazine and -simazine) was evaluated by ELISA and CMIA. The best tracer 9 (bearing the longest alkyl chain between atrazine aromatic ring and metal carbonyl complex) was used for further study by CMIA. Reproducible competitive standard curves were obtained by using anti-simazine antibodies in PBS buffer pH 7.4 with pre-incubation of various amounts of atrazine and antibodies for 1 h at 4xa0°C before addition of the tracer. This study demonstrates the feasability of using CMIA for pesticide determination, although the sensitivity of current CMIA format does not reach the 0.1 μg l −1 level required by E.U.

New and efficient synthesis of CpRe(CO)3 substituted steroids

Abstract Fulvenes generated from steroids have been efficiently engaged in a process implying nucleophilic or basic attack followed by a transmetallation reaction in the presence of BrRe(CO)5 to afford the corresponding CpRe(CO)3 substituted compounds. This new strategy is of relevant interest for the synthesis of new potential radiopharmaceuticals.

KO2/crown ether: a novel catalytic system for the hydrosilation and Tishchenko reaction of aromatic aldehydes

Abstract A new catalytic system KO 2 /18-crown-6 ether is reported to lead, in the presence of Et 3 SiH, to hydrosilation and Tishchenko reaction of aromatic aldehydes. The nature of the products obtained are shown to depend on aldehydes and experimental conditions.

Review on Bioorganometallic Chemistry and New Outcomes in the Synthesis and Substitution of Tetracarbonyl(pyrrolylimine) Complexes of Rhenium with Organophosphorus Ligands

: After a short review dealing with bioorganometallic chemistry, the synthesis of tetracarbonyl (pyrrolylimine) complexes of rhenium bearing chirality on the pyrrolyl ligands was reported.The reactivity of these compounds towards the substitution of one carbonyl ligand with triphenyl phosphine, tricyclohexyl phosphine and trimethyl phosphite was studied. The rhenium becoming a stereogenic center in that transformation, the resulting tricarbonyl species were obtained as mixtures of diastereomers, with diastereomeric excesses varying from 8 to 84%, according to the reaction conditions and the relative steric hindrances of the pyrrolylimine and the organophosphorus ligands. These bioorganometallics are potential CO releasing molecules that could be used in the field of medicinal chemistry.

Comparison of two means of attachment of an organometallic acid on gold surfaces by combining X-ray photoelectron spectroscopy and IR reflection spectroscopy

Two methods of immobilization of the butyric 4-oxocyclopentadienylmanganese tricarbonyl acid I on gold surface are presented: either through the assembly of a disulfide derived from the acid, or by coupling on a cystamine monolayer; the efficiency of these two ways are evaluated by IR reflection spectroscopy and X-ray photoelectron spectroscopy.

Rearrangement of 2,5-Bis(silylated)-N-Boc Pyrroles into the Corresponding 2,4-Species

The rearrangement of 2,5-bis(silylated)-N-Boc pyrroles in their 2,4-isomers is shown to proceed under mild acidic conditions. A reasonable mechanism, based on literature as well as experiments, is proposed to rationalize this transformation.

On a new catalyzed silylation of alcohols by phenylhydrosilanes

KOH–18-crown-6 ether is a valuable system for the catalyzed dehydrocoupling of alcohols with phenylhydrosilanes (Ph3SiH and PhMe2SiH).

New and efficient routes to CpRe(CO)3 substituted steroids

Two new methods for the formation of CpRe(CO)3 nsubstituted steroids are presented; both imply a one-pot procedure ninvolving a transmetallation process.