Synthesis of Pyrroles from Benzyl Isocyanoacetate

Lash, Timothy D.; Bellettini, John R.; Bastian, Jolie A.; Couch, K.

doi:10.1055/s-1994-25431

Cited by 82 publications

(33 citation statements)

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“…Thus, it took six steps just to produce the pyrrole that was used to make 1, with an overall yield of 45 %. [13,14] This long synthesis was necessary to produce a porphyrin with ethyl groups at the beta positions. Since the porphyrin moiety in dyad 3 has only hydrogen at each beta position, it can be gained directly from commercially available pyrrole, thus eliminating many steps.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin–Fullerene Dyads with Parachute Topology

Fazio

Durandin

Tkachenko

et al. 2009

Chemistry A European J

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The synthesis of a porphyrin-fullerene dyad with "parachute" topology is reported. To determine whether the dyad is "flexing" at room temperature, low-temperature NMR experiments were used. Computational modeling has shown the low-energy conformation of the dyad to be nonsymmetric. Although, (1)H NMR spectroscopy at room temperature is consistent with a molecule with C(2v) symmetry, the spectrum changes on lowering the temperature consistent with "windshield wiper"-like motion, in which the porphyrin moiety rotates from one side of the C(60) sphere to the other. Nanosecond and picosecond fluorescence lifetime experiments show two components contribute to the fluorescence decay, also consistent with the presence of more than one conformer.

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Section: Resultsmentioning

confidence: 99%

Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin–Fullerene Dyads with Parachute Topology

Fazio

Durandin

Tkachenko

et al. 2009

Chemistry A European J

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“…Die für diese Synthesen erforderlichen Nitroalkene sind einfach über eine Aldolkondensation von Nitroalkanen mit Aldehyden zugänglich; außerdem können sie ausgehend von O ‐Acetyl‐β‐hydroxynitroalkanen in situ erzeugt werden (Schema ) 24. Verwendet man anstelle von 1,8‐Diazabicyclo[5.4.0]undec‐7‐en (DBU) eine nichtionische Base wie 26 , die etwa 10 17 ‐mal basischer ist als DBU, werden die entsprechenden Pyrrole in hervorragenden Ausbeuten erhalten (Schema ) 25.…”

Section: Cocyclisierungen Metallierter Isocyanideunclassified

Isocyanide in der Synthese von Stickstoff‐Heterocyclen

2010

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Isocyanide bewähren sich seit langem als unersetzliche Bausteine in der modernen organischen Chemie. Die einzigartigen Eigenschaften der Isocyanogruppe machen Isocyanide für die Synthese etlicher wichtiger Klassen von Stickstoff‐Heterocyclen wie Pyrrolen, Indolen oder Chinolinen besonders wertvoll. In letzter Zeit wurde eine ganze Reihe von Cocyclisierungen von Isocyaniden über Zwitterionen und radikalische Intermediate ebenso wie übergangsmetallkatalysierte Synthesen verschiedener Arten von Heterocyclen entwickelt. Methoden, die von Isocyaniden ausgehen, weisen oftmals deutliche Vorteile gegenüber alternativen Wegen auf, was oft der verbesserten Konvergenz und der Einfachheit solcher Verfahren sowie der großen Vielfalt einfach zugänglicher Isocyanide geschuldet ist. So finden Isocyanide auch in enantioselektiven Synthesen chiraler heterocyclischer Verbindungen einschließlich Naturstoffen Verwendung.

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“…1) and substituted pyrrole 6 (see Ref. 16) were synthesized accord ing to known procedures. The 1 H and 13 C NMR spectra were recorded on a Bruker Avance 400 spectrometer (400.13 MHz for 1 H and 100.25 MHz for 13 C).…”

Section: Methodsmentioning

confidence: 99%

Alkylation of nitrogen heterocycles with 1,3-bis(hydroxymethyl)ferrocene. Generation of the ferrocene dicarbocation [{1,3-(CH2)2C5H3}Fe(C5H5)]2+

et al. 2010

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The alkylation of imidazole and 5 benzyloxycarbonyl 3,4 diethylpyrrole with 1,3 bis (hydroxymethyl)ferrocene (1) afforded bis imidazole (4) and bis pyrrole (7) derivatives of ferrocene, respectively. The reaction of diol 1 with trifluoroacetic acid gave the dicarbocationic complex [{1,3 (CH 2 ) 2 C 5 H 3 }Fe(C 5 H 5 )] 2+ (2) characterized by 1 H NMR spectroscopy.Previously, 1 we have reported on the phosphorylation of 1,3 bis(hydroxymethyl)ferrocene (1) giving ferrocene diphosphines {1,3 (R 2 PCH 2 ) 2 C 5 H 3 }Fe(C 5 H 5 ) (R = Pr i , Bu t ). The latter were used as the starting compounds for the synthesis of P,C,P pincer complexes with the ferrocene backbone. Rhodium, 1 palladium, 2,3 iridium, 4 and ruthe nium 5 bis(phosphine) pincer complexes with the ferrocene or ruthenocene backbone are presently known. These com plexes have attracted interest due to their ability to acti vate small molecules and hydrocarbon substrates and cat alyze a variety of reactions, among which of great impor tance is the homogeneous dehydrogenation. Recently, 4 it has been shown that the iridium complex IrH 2 [{2,5 (Bu t 2 CH 2 ) 2 C 5 H 2 }Fe(C 5 H 5 )] is the most active catalyst for alkane dehydrogenation among all known homogeneous systems.The chemistry of metallocene based pincer complexes is in its infancy. In the future, it is necessary to use in a greater extent the potential of these systems conditioned by the sandwich geometry of metallocenes and the ability to vary the metallocene central atom and its oxidation state in the case of the iron atom in ferrocene. It would expect that pincer complexes having the metallocene back bone would be used for the creation of new generation polymetallic catalysts and materials having useful photo physical and sensor properties. The progress in this area is related to the development of convenient methods for the synthesis of functionalized 1,3 disubstituted metal locenes, 3-9 which are nowadays much more difficult to synthesize compared to 1,1´ and 1,2 disubstituted ana logs. It is also necessary to design pincer ligands contain ing donor atoms other than phosphorus, for example, car bon atoms of N heterocyclic carbenes and nitrogen atoms of N heterocycles.In the present study, we describe the first results on the synthesis of precursors of new types of pincer ligands based on ferrocene. The alkylation of imidazole and substituted pyrrole with diol 1 afforded the diimidazole and dipyrrole derivatives of ferrocene, respectively. Results and DiscussionThe ferrocenylmethylation can be performed with the use of ferrocenylmethyl halides (rather unstable com pounds), ferrocenylcarbinols, or ferrocenylmethylammo nium salts. 10 These reactions proceed through the forma tion of α ferrocenyl carbocations, whose enhanced stabil ity is well known. 11 The ferrocene carbocations were char acterized by 1 H, 13 C, and 57 Fe NMR spectroscopy. The most stable of them, as well as their ruthenium and osmi um analogs, were isolated as crystalline salts and were studied by X ray diffraction. 11,12 Unlike fe...

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Synthesis of Pyrroles from Benzyl Isocyanoacetate

Cited by 82 publications

References 0 publications

Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin–Fullerene Dyads with Parachute Topology

Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin–Fullerene Dyads with Parachute Topology

Isocyanide in der Synthese von Stickstoff‐Heterocyclen

Alkylation of nitrogen heterocycles with 1,3-bis(hydroxymethyl)ferrocene. Generation of the ferrocene dicarbocation [{1,3-(CH2)2C5H3}Fe(C5H5)]2+

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