Iron-containing heterocycles,

The synthesis of only one iron-containing heterocycle was described between 1995 and 2006. The formation of paramagnetic 57 from a stable arylgold(i) phosphine, [Au( 7 -C-NCN)(PPh3)] 56 and anhydrous EeCls in toluene at... 

N-Heterocycles as ligands in dioxygen activation by enzymes with mononuclear nonheme iron-containing active sites 96CRV2607. 

The mechanism and synthetic scope of reactions of monohaptopropargyl-iron complexes has been described earlier (see Schemes 30-33 in Section IV,A,2). By using sulfur dioxide and sulfur trioxide as electrophilic reagents, it is possible to synthesize metal-containing heterocycles in the reduced 1,2-oxathiole category (sultines and sultones) (Scheme 119).182-184 An... 

A-Amine oxides can be reduced (deoxygenated) to tertiary amines. Such a reaction is very desirable, especially in aromatic nitrogen-containing heterocycles where conversion to amine oxides makes possible electrophilic substitution of the aromatic rings in different positions than it occurs in the parent heterocyclic compounds. The reduction is very easy and is accomplished by catalytic hydrogenation over palladium [736, 737], by borane [738], by iron in... 

Crude oil consists mainly of a mixture of paraffinic, naphthenic, and aromatic hydrocarbons with small amounts of metals-containing heterocyclic compounds. The most abundant metals found in oils are those contained in porphyrin or porphyrin-like complexes (nickel, copper, iron, and vanadium). These... 

The black trinuclear iron complex Fe3(CO)8(Ph2C2)2> one of two isomers obtained by the reaction of excess tolane with dodecacarbonyl iron, contains not only a heterocyclic iron atom similar to that first observed by Hock and Mills (36) but also has two iron atoms lying symmetrically on either side of the heterocyclic ring (42) in a manner similar to that suggested by the author on theoretical grounds (20) (Fig. 9). 

Tryptophan oxygenase is another iron-containing enzyme which, like catalase, is inhibited by pyrazole in vivo but not in vitro. Again, however, the metabolite 4-hydroxypyrazole is active in vitro and shows, in contrast to catalase, competitive inhibition with tryptophan for the enzyme (79MI10505). Adrenaline and other phenols are also inhibitors of this enzyme and in this case, therefore, the heterocyclic ring appears not to be essential for activity. 

Kandarpa, R, Anamika, J., Nirada, D. 2011. Characterization of an iron-rich kaohnite clay and its application as heterogeneous catalyst for the microwave-mediated dry synthesis of V-containing heterocycles. Research Journal of Chemistry and Environment 15 86-91. 

While the reaction is somewhat insensitive to the electronic effect of the substituent on the aryl group, it is very sensitive to any steric effects. The reaction of 2-o-tolylpyridine is very slow and yields little product due to restricted conformation. Nitrogen-containing heterocycles other than pyridine also undergo this ary-lation reaction. Some examples are shown above. In this interesting case of iron... 

Iron is an abundant, inexpensive, and environmentally benign metal in the first transition series with numerous important applications in a wide range of organic transformations and enzyme chemistry. In recent years, researchers have made impressive advances in the iron-catalyzed C-H bond activation [1]. These methods are successful through the formation of various C-C, C-N, and C-O bonds and have become prevalent and efficient tools to assemble valuable nitrogen- and oxygen-containing heterocycles. 

Iron-Catalyzed Synthesis of Nitrogen-Containing Heterocycles... 

Imidazopyridines are important nitrogen-containing heterocycles that show a wide range of bioactivities. Hajra and coworkers have developed an iron-catalyzed oxidative diamination of nitroalkene with 2-aminopyridine to access 2-nitro-3-arylimidazo[l,2- ]pyridines under mild and aerobic reaction conditions (Scheme 9.6) [8]. In particular, the method allows the formation of two new C-N bonds through sequential Michael addition and vinyl C(sp )-H/N-H functionalizations and represents the first example of employing molecular oxygen as the terminal oxidant for the selective C-H amination. 

An early report by Oddo suggested that a product containing two heterocyclic residues and one iron atom per molecule was obtained by the action of ferric chloride on the 2-methylindole Grignard reagent. - ... 

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