Ferrocenes ferrocene carboxaldehyde

The second-generation 02" biosensors are mainly based on the electron transfer of SOD shuttled by surface-confined or solution-phase mediators, as shown in Scheme 2(b). In 1995, Ohsaka et al. found that methyl viologen could efficiently shuttle the electron transfer between SOD and the glassy carbon electrode and proposed that such a protocol could be useful for developing 02 biosensors [125], Recently, Endo et al. reported an 02, biosensor based on mediated electrochemistry of SOD [148], In that case, ferrocene-carboxaldehyde was used as the mediator for the redox process of SOD. The as-developed 02 biosensor showed a high sensitivity, reproducibility, and durability. A good linearity was obtained in the range of 0 100 pM. In the flow cell system, tissue-derived 02 was measured. 

Pinacol coupling of 2-substituted ferrocene carboxaldehydes with samarium(ll) iodide in THF also affords dl-coupling products selectively. 

Enantioselective synthesis of /3-amino alcohols by Sml2-mediated cross-pinacol coupling of the planar chiral iV-sulfonyl(ferrocenylidene)amine with ferrocene carboxaldehyde is achieved by facile reduction of the ferrocenyli-dene amine with Sml2, followed by enantioselective addition to the aldehyde (Equation (75)). ... 

Ferrocene is similar to other highly reactive aromatic systems, in that it is readily formylated by N-methylformanilide in the presence of phosphorus oxychloride (5, 29, 107, 113, 118). Only the mono-substituted product, ferrocene-carboxaldehyde (XVI), is produced even when a large excess of formylating agent is used. 

A corresponding aldehyde [1.1 mmol, piperonal (a), ferrocene carboxaldehyde (b)] and ketone [1.0 mmol, acetylferrocene (a), 2-methylcyclohexanone (b)] were stirred in an Ehrlenmeyer flask, 2 mmol of powdered KOH added, and the mixture stirred after addition of one drop of Aliquat 336 [see (3.279) and (3.280)]. The Ehrlenmeyer flask was irradiated with microwaves [(a) 3 min, MOW (b) 2 min, MOW] and the final product dissolved in dichloromethane. After filtration on Celite, the solvent was removed and the residue chromatographed on a preparative chromatographic layer of silica (AcOEt/cyclohexane 20/80). The condensation product was further purified by crystallization in ether. Yield (a) 73% (lit. 37%), red solid (b) 63%, red solid. 

The reaction of ferrocene carboxaldehyde 83 with resorcinol 84 gave the macrocycle 85, which, on treatment with bromochloromethane, gave the first redox-active cavitand 86 [106,107], the X-ray crystal structure of which revealed the inclusion of CHjClj within the cavity. The same paper reported the synthesis of two related cavitands 87 and 88, but electrochemical investigations failed to produce significant changes in the CV when CH2CI2 was added to, or CO2 bubbled through, DMF solutions of 86 or 87. 

Aminothiazole reacts with both ferrocenecarboxaldehyde and ferrocenecarboxylic acid chlorideto give the expected imine and amide, respectively. Ferrocenecarboxylic acid chloride also reacts with phenothiazine to give both N- and C-acetylation. Ferrocene-carboxaldehyde and rhodanine gave 134, while reaction of the thiosemicarbazone of ferrocenecarboxaldehyde with chloroacetic acid in acetic acid gave 135. ... 

Bisimidazolylferrocenylmethane (32) can be prepared from the reaction of 1 and ferrocene carboxaldehyde at 80 °C in the presence of CoCl2-6H20 (eq 26). Methylation of (32) with CH3I in the presence of NFLjPFg affords the bis(methylimidazolium) salt (33), which is a precursor in the synthesis of some A-heterocyclic carbenes (NHCs). 

Ferrocene carboxaldehyde [12093-10-6] M 214.1, m 117-120°, 118-120°, 121°, 124.5°. The aldehyde forms red crystals from heptane/CH2Cl2, EtOH or petroleum ether and sublimes at 70°/lmm. The cyanohydrin has m 104° (from C6Hg/EtOH). The semicarbazone has m 217-219°(dec) after recrystallisation from aqueous EtOH. The oxime provides two isomers from petroleum ether viz m 96-99° and m 155°. The 0-acetyloxime has m 80-81° after recrystallisation from hexane [Lindsay Hauser J Org Chem 22 355 1957]. The 2,4-dinitrophenylhydrazone has m 248°(dec). Beilstein 16 IV 1798, Graham et al. JAm Chem Soc 79 3416 1957, Broadhead st al. J Chem Soc 650 7P58.]... 

Immobilization of complexing agents on electrode surfaces was achieved by several procedures. Lane and Hubbard first demonstrated the principle by adsorbing a salicylate ligand, which could complex Fe(III) solution species, onto platinum electrodes. Cox and Majda adsorbed adenosine monophosphate onto platinum electrodes to detect Fe(II) from solution using cyclic voltammetry. Price and Baldwin used ferrocene carboxaldehyde as a model analyte to investigate a modified electrode developed to determine aldehydes and ketones. The formation... 

However, slow leakage of the soluble form of the redox mediator (the ferrici-nium ion) may lead to biosensor deterioration and precludes its use for on-line monitoring. The use of soluble high molecular weight diffusing mediators should in principle limit this phenomenon. For this purpose, the protein BSA was labeled with Fc groups by reductive amination with ferrocene carboxaldehyde 3 in the presence of sodium borohydride (Scheme 6.1) and the labeled protein was shovm to behave as a redox mediator in the electrocatalysis of glucose by GOx 181. 

Ferrocene carboxaldehyde 3 and periodate-oxidized digoxigenin were covalently coupled to BSA lysine residues by reductive amination to yield a conjugate behaving as a multivalent antigen. Binding of antidigoxigenin antibody led to a concentration-related decrease of the oxidation current of the ferrocenyl groups [32]. 

Another approach of broader applicability has been described recently. We prepared the chiral acetal 12a derived from ferrocene carboxaldehyde and (S)-l,2,S-butane triol (Figure 10) This acetal was 0-methylated into 12b.The overall yield of 12b from ferrocene carboxaldehyde is about 70%. The structure was established by nmr. 

Chiral ferrocene carboxaldehydes 14 are now easily available in very high ee s, with predictable absolute configurations and are key compounds to reach a large range of fetrocenes with planar chirality. 

Complex 4 was prepared in good yield through a sequence involving selective transmetalation of the tri-n-butylstannyl groups combined with established condensation chemistry of ferrocene carboxaldehydes (Scheme Compound 4... 

Unsymmetrically disubstituted ferrocenes have been prepared also from ferrocene carboxaldehyde by first converting the aldehyde to the /3-(methoxycarbonyl)ethenylferrocene which may be formylated at the 1 -position. A series of ferrocenophanes such as 54 were then obtained in two steps from the formylated products." " " ... 

Ferrocene also undergoes the Vilsmeier reaction to yield ferrocene-carboxaldehyde, which is a useful starting material for the synthesis of other ferrocene derivatives, for example by condensation with compounds containing active CH2 groups such as malonic acid ... 

Aydemir and co-workers used chiral aminoalcohols to prepare phosphinites 118a-b (Scheme 30), through the reaction of the aminoalcohols with ferrocene carboxaldehyde, followed by reaction with chlorodiphenylphosphine. The ligands were tested in ruthenium(ii)-catalysed transfer hydrogenation of acetophenone derivatives, using isopropanol as the hydrogen source, with high conversions and enan-tioselectivities of up to 85% ee. 

Fang and coworkers attached ferrocene carboxaldehyde to an amino-tagged oligonucleotide and also showed it to be redox-active. The label was attached to denatured calf thymus DNA, and it was shown that binding of the complementary strand can be detected down to 5 X 10 M. 

The fluorenyl-ferrocene based NLO-phores have were prepared by condensing 2-bromo-, 2,7-dibromofluorene, and 2-nitrofluorene with ferrocene carboxaldehyde to afford 2a, 3a, and 4, respectively, all in reasonable yidd. For 2-nitrofluorene the base used is potassium tert-butoxide and for the bromofluorenes, lithium diisopropylamide (LDA). Complexes 2a and 3a undergo clean halogen-metal exchange Ity treatment with n-BuLi in tetrahydrofiiran (THF) at -78 °C and are thm converted to their respective carboxaldehyde and tributylstannyl derivatives by... 

The ferrocenyl fragment has also been bound covalently to a variety of copolyaspartamides via spacer groups attached to the aspartamide nitrogen atoms [61]. Attachment of ferrocene to carrier polymers, for example 50, 51, and 52, was brought about by reaetion of the amine functions attached to the spacer with ferrocenecarboxylic acids and -carboxaldehydes. The reactions shown in Scheme 10-24 are representative of these modifications. 

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