Pyrrole has been a molecule of great interest due to its heterocyclic aromatic properties. The lone pair on the nitrogen is delocalised within the ring, causing the heterocycle to be electron-rich . This causes the ring to become increasingly nucleophilic, and therefore makes it susceptible to attack from electrophiles . The addition of these new substitutions makes more important molecules , which have a huge contribution to not only the chemical industry, but also the biological. 1 Substituted pyrrole molecules are fantastic precursors to make complex molecules, such as medicines, agrochemicals and dyes. Indole, an important benzo-pyrrole, is the basis of the important protein, tryptophan and has functions as a neurotransmitter in the brain. The neurotransmitter, serotonin, is important in making modern drugs such as sumatriptan which treats migraines.2
Pyrrole synthesis can be achieved by a vast number of methods. Some of the most common processes used in today’s laboratory include the Hantzch pyrrole method, Paal-Knoor Knorr synthesis and the Knoorr synthesis; the latter which will be studied in this experiment. Other complex methods explored include Robinson’s utilization of the reaction between an aldehyde and a hydrazine . However, this method requires high temperatures which are not economically favourable to maintain and so the other classic methods are gene...
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...ential of the reaction and products.
1. V. Amarnath, D. C. Anthony, K. Amarnath, W. M. Valentine, L. A. Wetterau, D. G. J. Org. Chem. 1991, 56, p. 6924-6931.
2. J. Clayden, N. Greeves, S. Warren, P. Wothers. Organic Chemistry. 8th ed. 2007, Oxford University Press, p. 1186-1191.
3. G. M. Robinson, R. Robinson. J. Chem. Soc. 1918, p. 639-645.
4. A. H. Corwin. Heterocyclic Compounds. 1950, 1, p. 287.
5. Y. Byun, D. A. Lightner. J. Heterocyclic Chem. 1991, 28. p. 1683-1692.
6. Professor Chris Willis, School of Chemistry, University of Bristol
7. Professor Kevin Booker-Milburn, 2nd Year Heterocyclic notes, School of Chemistry, University of Bristol
8. H. Fischer. Organic Syntheses Coll. 1943, 2, p. 202; H. Fischer. Organic Syntheses Coll. 1935, 15, p. 17.
9. C. Schmuck, D. Rupprecht. Synthesis 2007, 2007, 20, p. 3095-3110.
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