reaction of various arylamine with acetones and styrenes. The
reaction afforded the corresponding products in moderate yields
with good functional group tolerance. This strategy offers a new
method to directly synthesize multi-substituted pyrroles using
simple and inexpensive reactants via a combination of 1,4-
dicarbonyl synthesis and Paal-Knorr type condensation reactions.
concluded that this reaction was affected by both electronic and
steric factors.
Additionally, other aromatic amines such as 1H-pyrazol-3-
amine (4v, 63%) or substituted styrenes such as 4-chlorostyrene
(4w, 67%) and 4-methylstyrene (4x, 57%) were transformed into
the corresponding products. However, the heterocyclic alkenes 4-
vinylpyridine, 2-vinylpyridine and 2-vinylthiophene did not
proceed or reacted with low yields.
Acknowledgments
The work was supported by the Program for Innovative Research
Team of the Ministry of Education and Program for Liaoning
Innovative Research Team in University (IRT1073).
1) Cu(OTf)2 (5 mol%), TBHP
NH2
MnCl 2•4H2O (5 mol%), DBU
O
N
2) 3, HSO3NH2
A. Supplementary data
68% (one-pot, 24 h)
64% (two separate step, 36 h)
4a
1
2
3
Supplementary data associated with this article can be found,
Scheme 2. Comparison of one-pot and two step routes for the
formation of 4a.
References and notes
Finally, the one-pot reaction and the stepwise synthesis of
compound 4a was compared (Scheme 2). The reaction of styrene,
acetone and aniline, as depicted in Table 2, gave the
corresponding pyrrole in 68% yield (24 h) using the one-pot
method and in 64% yield (>36 h) if 1-phenylpentane-1,4-dione
was purified before the cyclization step. Compared to stepwise
synthesis, the one-pot method has the advantages of higher yield,
shorter reaction time, and simple operation. More importantly,
the one-pot method allows the direct synthesis of multi-
substituted pyrroles using simple and inexpensive reactants.
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8,9
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Conclusion
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In summary, we have developed a simple and efficient one-
pot synthesis of 2-methyl-1,5-diaromatic-1H-pyrroles, via the