Synthesis phenylpyrroles

Trofimov, B. A., M.V. Markova, L.V. Morozova et al. 2010. Cationic and radical polymerization of N-vinyl-2-phenylpyrrole Synthesis of electroconducting, paramagnetic and fluorescent oligomers. Synthetic Met 160 1539-1543. 

The simplicity of the PK pyrrole synthesis often makes it the method of choice. The preparation of 2,5-dimethyl-1-phenylpyrrole from 2,5-hexanedione and aniline is an undergraduate laboratory experiment," and applications of the PK reaction in research... 

The reader is referred to the simple undergraduate laboratory synthesis of 2,5-dimethyl-1-phenylpyrrole in the Journal of Chemical Education. ... 

Two unique type Had syntheses of pyrroles that were reported both involved cyclopropane fragmentations. The first allowed for a synthesis of 2-arylpyrroles <06SL2339>. In the event, treatment of stannylcyclopropane 25 with -BuLi followed by benzonitrile produced 2-phenylpyrrole 26 via tin-lithium exchange, addition to the nitrile, ring fragmentation of ketimine intermediate, intramolecular condensation, and loss of dibenzylamine. 

Bossio R, Marcaccini S, Pepino R, Torroba T (1999) Studies on isocyanides and related compounds. A facile synthesis of 1-substituted 3-cyano-2-methoxy-3-phenylpyrroles. Heterocycles 50(1) 463 167... 

Similar results have been obtained in studying the reaction of acetophenone oxime with acetylene (Scheme 2) 2-phenylpyrroles 3 and 4 are formed only in DMSO. When the synthesis is performed in sulfolane, only trace amounts of the pyrroles are observed, whereas in dimethylfor-... 

It was intended (85KGS1501) to find milder synthetic conditions for further simplifying the purification of 3-alkyl-2-phenylpyrroles (5,6) (Scheme 5). It was necessary to increase the DMSO content of the reaction mixture. So, when the synthesis was carried out under pressure in a 10-fold excess (of the total mass of reagents) of DMSO with an equimolar (with respect to ketoxime) amount of KOH, it was possible to decrease considerably the reaction temperature (to 50-60°) and prepare 3-alkyl-2-arylpyrroles (5) and their 1-vinyl derivatives (6) (which more readily undergo purification) in total yield up to 90%. 

Phenylpyrroles fludioxonil Protein kinase (in glycerol synthesis) 4 Protein kinase (os 2) and ABC transporter gene (BcatrB) ... 

The reaction of the ketene-A S-acetals 15 with ethyl bromoacetate in the presence of base gave the 1-phenylpyrroles 16. Precursors 15, easily obtained from 1,3-dicarbonyl compounds and isothiocyanetes followed by S-alkylation, may also serve as starting materials for the synthesis of 2-aminothiophenes by reaction with ethyl thioglycolate <03T1557>. 

A wide variety of pyrvinium salts (1) have been prepared by treating a quinoline quaternary salt (41) with 2,5-dimethyl-l-phenylpyrrole-3-carboxaldehyde (40) [42,43]. The latter is obtained by a Paal-Knorr synthesis starting with 2,5-hex-anedione (37) and aniline [44,45] (Scheme 1). 

This is followed by an example of a pyrrole synthesis DIMETHYL-3-PHENYLPYRROLE-2,5-DICARBOXYLATE is obtained via an inverse demand Diels-Alder synthesis using DIMETHYL-1,2,4,5-TETRAZINE-... 

A titanium-promoted cyclization of 1,3-diketones with imines or oximes led to highly substituted pyrroles <04SL2239>. A nitroso group served as a novel source of nitrogen in a pyrrole synthesis. Treatment of l,4-bis(bromomagnesium)butadiene derivatives with nitrosobenzene (PhNO) gave A-phenylpyrroles <04CEJ3444>. 

The total synthesis (Scheme 25) of ( )-rhazinilam was achieved by viewing the alkaloid as a derivative of a 3-phenylpyrrole. Thus 2-methoxycarbonyl-4-(2-nitrophenyl)pyrrole was first synthesized and then the aliphatic portion of the molecule introduced by alkylation at the pyrrole nitrogen [ —>(111)] and the carbon skeleton completed by intramolecular Friedel-Crafts alkylation [— (112)] at the only available pyrrole a-position. 

In 1972 van Leusen described a simple synthesis of 4-phenylpyrroles bearing a cyano-, a keto- or an ester-group in the 3-position of the pyrrole ring, using TosMIC (5) as a key reagent (Scheme 15.2.1) [12]. 

Dimethyl acetylenedicarboxylate added to a soln. of 2-amino-3-cyano-4,5-dimethyl-1-phenylpyrrole in acetic acid, and stirred at room temp, until precipitation complete - product. Y 85%. F.e.s. K. Eger et al., Synthesis 1988, 632-5. 

Kim SK, Jun C, Kwak K, Park K, Chai K (2007) Synthesis of N-alkylated 4-fluoro-5-phenylpyrrole-2-carboxylate via isolable pyrroUne ionic intermediates. Bull Korean Chem Soc 28 2324-2328... 

AlClg added under argon to a mixture of acetophenone phenylhydrazone and dimethyl acetylenedicarboxylate in benzene, and stirred 1 hr. at room temp. 2,3-bis(methoxycarbonyl)-5-phenylpyrrole. Y 74%. F. e. s. J. Barluenga, F. Palacios, and V. Gotor, Synthesis 1975, 642. 

Table 3.12 Probable and implemented methods for the synthesis of pyrrolo[l,2-a] quinoxalines based on phenylpyrrole derivatives...

This new synthesis of 3-alkyl(phenyl)-2-phenylpyrroles has been extended over alkyl aryl ketoximes (Scheme 1.46) [163,221], As a consequence, earlier unknown or difficult to produce 2-arylpyrroles can be synthesized using this methodology. 

SCHEME 1.112 Synthesis of 2,3-disubstituted-5-phenylpyrroles from ketoximes and phenylacetylene in the KOH/DMSO system. 

SCHEME 2.117 Synthesis of stable enol from 2-(l-ethylthio-2-carbamoyl-2-cyanovinyl)-5-phenylpyrrole in the presence of NaOH in aqueous MeOH. 

The possibility of structures B formation from pyrroles and acetaldehyde is confirmed by the synthesis of di-(N-vinyl-5-phenylpyrrol-2-yl)methane (46% yield. Scheme 2.190) from 2-phenyl-N-vinylpyrrole and formaldehyde in the dilute acetic acid (dioxane, 70 C-80 C). The intermediate 5-hydroxymethyl-2-phenyl-N-vinyl-pyrrole is isolated in 3% yield [649]. 

Synthesis by Direct Cross-Coupling Reaction Trauner and co-workers and Bowie and Trauner reported on a concise total synthesis of racemic rhazinilam 122 and rhazinal 123, axially chiral phenylpyrroles having potent antimitotic properties, through an aromatic C—H activation (Scheme 23.24). " To construct the lactam ring of the title compounds, the authors proposed the use of a palladium-catalyzed direct intramolecular cross-coupling reaction. 

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