Lectures in Heterocyclic Chemistry   Collected and organized by Prof. Dr. Adel Awadallah Islamic University of Gaza (2015)

Lectures in Heterocyclic Chemistry  (Collected and organized by Prof. Dr. Adel Awadallah) Text Book Heterocyclic Chemistry, T. L. Gilchrist   Other Books and References  * Heterocyclic Chemistry, R. Gupta, M. Kumar, V. Gupta * Heterocyclic Chemistry, J. A. Joule, G. F. Smith * An Introduction to the chemistry of Heterocyclic compounds, R. M. Acheson * Comprehensive Heterocyclic Chemistry, edited by: A. R. Katritzky and C. W. Rees * Journals in organic and heterocyclic chemistry such as J. Heterocyclic Chem. Heterocycles Molecules (open access journal) Synthetic communications J. Organic Chemistry

Nomenclature of Heterocyclic Compounds  Systematic Nomenclature system: (Hantzsch-Widman System)

Fused Rings

Naming Heteromonocycles Prefix (heterotoms, number, positions) + Stem (ring size + saturation)

Azirine Oxepin

Examples: Name the following compounds

Indication of saturated positions 1 position (H) 2 positions (dihydro) 3 positions (dihydro + H) 4 posit ions (tetrahydro) 5 positions (tetrahydro + H)   Saturated positions receive the lower number

Examples:

Compounds containing exocyclic C=O and C=S

Nomenclature of fused ring systems Prefix(O) + Base component

Base Component 2) No, Nitrogen, oxa then thia 1) One ring only contains N, Choose it 2) No, Nitrogen, oxa then thia

3) One consists of two or more rings, choose it 4) Two rings of different size, choose the larger

5) Choose the one with more heteroatoms 6) Same number of heteroatoms, choose oxa > thia > aza

7) Same number of heteroatoms, same oxa, thia, aza, then choose lower numbering

Indicate the fusion by giving letters to the base components and numbers to the prefix (go in the same direction)

Numbering substituents on fused rings: Use rectangular coordinates As many rings as possible lie in a horizontal row A maximum number of rings are in the upper right quadrant The system is numbered in a clockwise direction commencing with that atom which is not engaged in the ring fusion and is furthest to the left: in the uppermost ring or in the ring furthest to the right in the upper row

C atoms which belong to more than one ring are omitted Hetero-atoms in such positions are, however, included  

If there are several possible orientations in the coordinate system, a) Give low numbers for the heteroatoms as a set

b) Give low numbers for hetero-atoms when considered in the order (O, S, N)

c) Give low numbers to fusion carbon atoms

d) Give low numbers to indicated saturated atoms

Examples: