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Alkylpyrroles oxidation

The nitrosation of pyrroles and indoles is not a simple process. The 3-nitroso derivatives (84) obtained from indoles exist largely in oximino forms (85) (80IJC(B)767). Nitrosation of pyrrole or alkylpyrroles may result in ring opening or oxidation of the ring and removal of the alkyl groups. This is illustrated by the formation of the maleimide (86) from 2,3,4 -trime thylpyrrole. [Pg.56]

Nitrosation of pyrrole or alkylpyrroles may result in ring opening or oxidation of the ring and removal of the alkyl groups. This is illustrated by the formation of the maleimide (119) from 2,3,4-trimethylpyrrole. [Pg.317]

Similarly, 3-alkylpyrroles are relatively insensitive to halogenation and mild oxidation. Evidence has been obtained to show that halogenation of polysubstituted 2-methylpyrroles at low temperature in the dark occurs via the initial rapid electrophilic attack at any one of the annular carbon atoms with a subsequent slower shift of the halogen to the side chain... [Pg.270]

Furans can be converted into N- alkylpyrroles by heating with primary amines and alumina. Similar thermal conversions of furans and benzo[6]furans to their sulfur analogues in the presence of alumina or other metal oxide catalysts and hydrogen sulfide are also known. l,3-Diphenylbenzo[c]furan is converted into the thiophene by heating with phosphorus pentasulfide. The mechanism of these reactions is obscure. [Pg.613]

With strong oxidizing agents such as chromium trioxide in aqueous sulfuric acid, alkylpyrroles are converted into maleimides, e.g., 154. This oxidative technique played an important part in the classical determination of porphyrin structures. Milder oxidizing agents, such as hydrogen peroxide, convert pyrroles into pyrrolinones, e.g., oxidation of the parent heterocycle gives a tautomeric mixture of pyrrolin-2-ones 155 and 156. [Pg.418]

The behavior of 1-alkylpyrroles to autoxidation was studied by Smith and Jensen12 with 1-methyl-, 1-isopropyl-, and 1 -w-butylpyrrole. It was found that N-alkylpyrroles reacted much more slowly with oxygen than C-alkylpyrroles. The reactions were characterized by an induction period, during which the colorless liquid turned yellow and no oxygen uptake was detected successively an autocatalytic reaction took place. The simple oxidation products formed in the case of 1-methylpyrrole were isolated and the structures 10-13 assigned. [Pg.70]

Peroxides were observed to be present even in very lightly oxidized samples,12 and this seems to suggest that they are among the earliest reaction products. Since there is evidence that pyrroles exhibit a diene character in the presence of radicals,13,14 it seems reasonable to assume that the oxidation of 1-alkylpyrroles may occur mainly by radical addition. A possible mechanism was, in fact, postulated.12 The observed differences in the oxidation rates on varying the alkyl group must be due to steric hindrance of bulky substituents at the electronically preferred a. positions. [Pg.71]

In Table I other examples of the oxidation of alkylpyrroles reported in literature are listed. [Pg.83]

Oxidation of Some Alkylpyrroles with Hydrogen Peroxide... [Pg.83]

Triazoles and Benzotriazoles. - The alkenediazonium salt (431 Ar = P-NO2C6H4) is converted into the triazoles (432 R = H or alkyl) by the action of amines. Anodic oxidation of the oxime phenylhydrazone of benzil, HON=CPhCPh=NNHPh, gives the AA-oxide (433). The alkenyl-triazolines (434 R = H or alkyl) afford the aziridines (435) on flash vacuum py roly sis.Photolysis of the 4-alkylaminotriazoles (436 R = alkyl) yields 2-alkylpyrroles rather than the expected 3-alkyIpyrroles. The... [Pg.260]

Kou, C.T., and T.R. Lion. 1996. Characterization of metal-oxide-semiconductor field-effect transistor (MOSFET) for polypyrrole and poly(N-alkylpyrrole)s prepared by electrochemical synthesis. Synth Met 82 167. [Pg.347]

Poly(3-alkylpyrrole)s are, like PP, stable only in the oxidized state and their solubility is very poor. [Pg.69]

Hyperbranched poly(acrylic acid) films have been grown on SAMs of alkanoic acid [137]. These films, rich in carboxylic acid groups could be utilized to selectively bind metal ions or serve as sites for further derivatization. Wurm et al. have studied electrochemically induced epitaxial polymerization [135] of iV-alkylpyrrole in solution onto a SAM composed of ((A -pyrrolyl)-n-undecyl)disulfide. These optically smooth films of long chain poly(iV-alkylpyrrole) have excellent stability in air. The Collard group [142] has studied the kinetics of electro-oxidatively polymerized polyaniline and polypyrrole on surfaces modified with SAMs formation of conducting films is initially blocked by the monolayer but nucleation at SAM defect sites leads to eventual deposition of rough polymer films. [Pg.937]

Poly(3-alkylpyrroles) can also be obtained by FeCl3 polymerization, with conductivities around 10 S cm , being soluble in CHCI3 and dichlorobenzene in the oxidized state [191,192]. Poly(3-octylpyrrole) has also been prepared by oxidative coupling using Cu(C104)2 and Fe(C104)3 [193,194]. [Pg.444]


See other pages where Alkylpyrroles oxidation is mentioned: [Pg.57]    [Pg.118]    [Pg.115]    [Pg.199]    [Pg.318]    [Pg.57]    [Pg.118]    [Pg.357]    [Pg.432]    [Pg.57]    [Pg.357]    [Pg.183]    [Pg.96]    [Pg.51]    [Pg.52]    [Pg.256]    [Pg.82]    [Pg.247]    [Pg.207]    [Pg.256]    [Pg.69]    [Pg.774]    [Pg.154]    [Pg.455]    [Pg.490]    [Pg.86]    [Pg.82]    [Pg.238]   


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Alkylpyrroles

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