Ferrocenyl catechols

Ferrocenyl catechols 8 and 9 also exhibited interesting cytotoxic activities. On MDA-MB-231 breast cancer cell lines, the catechol compounds displayed a similar or greater antiproliferative potency (IC50 values ranging from 0.48 to 1.21 p,M) than their corresponding phenolic analogs (0.57-12.7 p.M) in complete agreement with their easiest oxidation [28]. 

Catechol is an intermediate for the synthesis of racemic adrenaline which, although quite medicinally active, can be resolved (ref. 36) in 71% yield to afford the more active R(-) enantiomer, the natural form, which can also be derived quantitatively by asymmetric reduction (ref. 37) of the synthetic precursor, adrenalone as the hydrochloride by catalytic hydrogenation in methanol containing the rhodium complex of (R)-o[(S)-1 ,2-bis(diphenylphosphine)ferrocenyl]ethyl alcohol. Adrenalone is obtained by the acylation of catechol with chloroacetyl chloride to afford 3,4-dihydroxy-w-chloroacetophenone followed by reaction with methylamine. 

It has been shown that tamoxifen and hydroxytamoxifen metabolize to 3,4-dihydroxytamoxifen [126]. This catechol can be oxidized by enzymes into ortho-quinone, which can react with DNA and proteins. A number of ferrocenyl catchols have been synthesized [127] (Fig. 42.9). 

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