Oxidation by ferric chloride

Cyclopropanols are also easily oxidized by ferric chloride either in ether or when dispersed on silica gel in the absence of any solvent (equation 10) ". ... 

Z. Zhang, J. Deng, and M. Wan, Highly crystalUne and thin polyaniline nanofibers oxidized by ferric chloride. Mater. Chem. Phys., 115, 275-279 (2009). 

Describe the mechanism and write the chemical equations for coordinated anionic polymerizations of propylene oxide by ferric chloride and by diethylzinc-water. Show the reaction mechanism. 

Little meaningful physical data on these complexes has appeared yet. The study of their reactivity is complicated by the effects of the substituents on the cyclobutadiene ring and the other ligands present. Until more information is available on the properties of the recently prepared unsubstituted cyclobutadieneiron tricarbonyl (XVIII) 38) and similar molecules, it is hard to be certain which properties are due to the presence of a cyclobutadiene group. Thus while cyclobutadieneiron tricarbonyl (XVIII) is easily oxidized by ferric chloride in ethanol (as are other diene-iron tri-carbonyl complexes, albeit to different types of product), tetraphenyl-cyclobutadieneiron tricarbonyl (XIII) is very resistant to this reagent, and indeed to most others, presumably mainly due to the steric hindrance of the phenyls. 

In an attempt to improve solution and melt processability of polythiophene, researchers [96] recently prepared thiophene-dimethylsiloxane homopolymers. First, 3-allythiophene and a dimethylsiloxane oligomer containing 4 siloxane units are reacted in the presence of a platinum catalyst. Next, the thiophene ring is oxidized by ferric chloride in chloroform for 24 hours. 

The data of Barger and Ewins did not permit definite allocation of the position of the sulfur atom in ergothioneine, but the stability of the sulfur toward alkali and its ready oxidation by ferric chloride or bromine water suggested the presence of a 2-mercaptoimidazole ( thiolimidazole ) structure. Confirmation of this was provided by Akabori (1933), who reduced the alkali-degradation product (thiolurocanic acid) with sodium amalgam to give 8-2-mercaptoimidazole-4(5)-propionic acid. The structure of this compound was confirmed by synthesis (III) from glutamic acid. 

Isopropylidene or benzylidene 2-hydrazinoselenazole derivatives can be converted to highly colored 2.2 -dioxo-A-3,3 -biselenazol-5,5 -inylidene-bis-hydrazones (Table X-11) by oxidation with ferric chloride and hydrogen peroxide i33). 

Later, Torii et al. found that the tin-aluminum-mediated allylation can be carried out with the less expensive allyl chloride, instead of allyl bromide, when a mixture of alcohol-water-acetic acid was used as the solvent.77 When combined with stoichiometric amounts of aluminum powder, both stoichiometric and catalytic amounts of tin are effective. As reported by Wu et al., higher temperatures can be used instead of aluminum powder.78 Under such a reaction condition, allyl quinones were obtained from 1,4-quinones, followed by oxidation with ferric chloride. Allylation reactions in water/organic solvent mixtures were also carried out electrochemically, with the advantage that the allyltin reagent could be recycled.79... 

Water, methanol, and n-hexane do not influence the photooxidation of PVC (43), but the photodegradation is accelerated by ferric chloride (70,71) and certain other compounds containing iron (70,71,72). Purification of the polymer might be expected to enhance its photostability by removing deleterious impurities such as iron compounds that are derived from metal equipment. This type of result was obtained in one recent study (58) but not in others (30,59). In contrast, the photo-oxidative degradation of PVC should be enhanced by admixture of the polymer with materials that are unusually susceptible to photooxidation themselves. Such behavior has been observed for impact-modified PVC containing polybutadiene-based polyblends (69,73). 

Accordingly, the cyclopropenylidene anthrones 190/198 were converted by ferric chloride in hydroxylic solvents to the allene ketal 466, whose hydrolysis gives the allenic ketone 46 7288. The dioxolane 468 was obtained from the alkyl-substituted quinocyclopropene 190 in glycol and the ketone 467 in methanol. Apparently FeCl3 served not only as an oxidant, but also as a Lewis acid assisting solvent addition to C1 2 of the triafulvene. 

Hydroxylamine (NH2 OH) is oxidized by ferric iron in boiling sulphuric acid - an oxide of nitrogen being amongst the products. 25.00 cm3 of a solution of hydroxylamine (2.00 g dm 3) were boiled with an excess of ferric chloride in dilute sulphuric acid. 30.30 cm3 of potassium permanganate solution (0.0200 M) were required to reoxidize the ferrous ions produced. Deduce the identity of the oxide of nitrogen. 

Dihalogenation of oxindole followed by alkaline hydrolysis of the 3,3-dihalooxindole has been applied to the synthesis of some isa-tins.66,126,136 137b A number of oxindoles have been treated with nitrous acid to give isatin-3-oximes.100,138 Reduction of the oximes to 3-aminooxindoles followed by ferric chloride oxidation gave isatins.100,138 When this sequence was applied to 7-azaoxindole, the azaisatin 33 was... 

The first information about the synthesis of naptho[bc]-oxete 11 (33BRP394511) was incorrect (70JOC4261). Oxidation of a-naphthol by ferric chloride or the attempted dehydration of 1,8-dihydroxynaphthalene 10 led to complex mixtures where the desired compound 11 was not detected (70JOC4261). 

The oxidation of ethyl indoxylate to ethyl indox-anthinate6 and of naphthol to dinaphthol may be accomplished by ferric chloride ... 

The last-named is also obtained when hydrogen fluoride is passed over red-hot iron, ferric oxide, or ferric chloride 4 or by heating the double salt, ferric ammonium fluoride, FeF3.3NH4F, in an inert gas. 

Only a very few 4,4 -bis(2-pyrazolin-5-ones) linked by a double bond have been prepared. The parent compound of this series, 4-(3-methyl -1 -phenyl - 5 - oxo - 2 - pyrazolin - 4-ylidene)-3-methyl-l-phenyl-2-pyrazolin-5-one (XXII-D), is known as pyrazole blue.323,807,809,816, 1090,1091 was so nameci by Knorr because of its great resemblance to indigo blue. All these compounds are strongly colored. The usual synthesis is by ferric chloride oxidation of monomeric 2-pyrazolin-5-ones (eq. 61)296,809 or by oxidation of the corresponding bis compounds... 

Of a variety of metal compounds described in this section, iron compounds represented by ferric chloride (FeCF) and potassium ferricyanide [K3Fe(CN)6] have long been used for phenolic oxidation, particularly for biomimetic syntheses of benzylisoquinoline alkaloids and neolignans ° . ... 

The bioactive benzimidazolequinone 131 has been synthesized by demethylation of the dimethoxybenzimidazole 129 followed by facile oxidation of the intermediate dihydroxy compoimd 130 by ferric chloride to yield the quinone 131 in excellent yield (Scheme 23). Synthesis of the related ben-zimidazolequinones 134 was achieved by dinitration of 132 followed by the reduction of 133 and oxidation as above. The benzimidazole-6,9-dione 134 has been found to be 300 times more cytotoxic towards the human skin fibroblast cell line in the MTT assay than the clinically used bioreductive drug, mitomycin C. Attaching methyl substituents onto the quinone moiety increased reductive potential and decreased cytotoxicity and selectivity towards hypoxia [67]. 

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