CHEMISTRY OF HETEROCYCLIC COMPOUNDS
Knowledge of basic organic chemistry is required, notably concerning properties and reactivity of the aromatic systems.
The main purposes of the course are:
- Provide a systematic knowledge of the behavior of hetero(poly)cyclic compounds, analyzing their structural properties and their reactivity.
- Provide an overview of the most important synthetic strategies for the synthesis of the heterocyclic systems, with particular attention to the intermediates involved in the reactions.
1. Structure of the heterocyclic systems (4 h). Nomenclature of three- to seven-membered heterocyclic rings. Nomenclature of the main heteropolycyclic systems. Electronic distribution of the following heteroaromatic systems: furan, pyrrole, thiophene and benzofused derivatives; pyridine and benzofused derivatives; pyrylium salts, imidazole, oxazole, thiazole, isoxazole; diazines and benzofused derivatives; polyazoles and polyazines. Basicity of nitrogen-containing heterocyclic systems.
2. Reactivity of heterocyclic systems (12 h). Reactivity of heteroaromatic systems: behaviour towards electrophiles, nucleophiles, reducing and oxidant agents. Alkene-type behavior and reactivity at benzylic position. Hydroxy-substituted heteroaromatic systems: keto-enol tautomerism and reactivity as nucleophile. Amino-substituted heteroaromatic systems: basicity and diazotization reaction. Aromatic nitrogen-containing heterocycles N-oxides: synthesis, electronic distribution, reactivity. Quaternary salts of aromatic nitrogen-containing heterocycles.
3. Strategies for heterocyclic synthesis (24 h). Intramolecular heteroaromatic nucleophilic substitution, intramolecular heteroaromatic electrophilic substitution, intramolecular condensation reactions, cyclocondensation reactions.
4. Ring-opening reactions of heterocycles (4 h). Ring-opening reactions of 1,2- and 1,3-five-membered heterocycles. Reactions for the conversion of heterocycles. Mesoionic compounds.
5. Some classes of heterocyclic compounds (4 h). Nucleosides, nucleotides, nucleic acids, -lactam antibiotics, porfirines, phthalocyanines, indigoid dyes.
Frontal lectures and exercises.
1) G. Broggini, G. Zecchi, E. Borsini, Chimica degli eterocicli, Terza Edizione, laScientifica.it, 2012.
2) J.A. Joule, K. Mills, Heterocylic Chemistry, Blackwell Science, 2000.
3) Jie Jack Li “Name reactions in Heterocyclic Chemistry”- Wiley
The final examination involves either a written test or an oral test. The former ensures the acquisition of knowledge and skills expected by performing application exercises. The oral test, which starts from a revision of the written test, is directed to check the ability of elaboration of the knowledge acquired.