Differences between the Basic and General aromatization methods

    The two method approach the question differently. The general method tries to incorporate mesomeric, tautomeric rearrangement, as in 2-pyridone, while the basic method does not. In the basic method the external double bond breaks the formation of aromatic ring.

    The 2-pirydone is aromatic due to its mesomeric rearrangement:

    images/download/attachments/1806797/pyridone_mesomer.png

    The following molecules will give different results depending upon the method applied.

    Molecule in aliphatic form Basic aromatization General aromatization
    IUPAC name: pyridin-2(1H)-one
    images/download/thumbnails/1806797/1.png images/download/thumbnails/1806797/1.png images/download/thumbnails/1806797/1_d.png
    IUPAC name: 2-thioxo-2,3-dihydropyrimidin-4(1H)-one
    images/download/thumbnails/1806797/2.png images/download/thumbnails/1806797/2.png images/download/thumbnails/1806797/2_d.png
    IUPAC name: 2,4-dihydro-3H-1,2,4-triazol-3-thione
    images/download/thumbnails/1806797/3.png images/download/thumbnails/1806797/3.png images/download/thumbnails/1806797/3_d.png
    IUPAC name: 9H-xanthen-9-one
    images/download/attachments/1806797/4.png images/download/attachments/1806797/4_c.png images/download/attachments/1806797/4_d.png
    IUPAC name: 5-thioxo-1,2,4-triazolidin-3-one
    images/download/thumbnails/1806797/5.png images/download/thumbnails/1806797/5.png images/download/thumbnails/1806797/5_d.png
    IUPAC name: imidazo[1,5-a]pyridine-3(2H)-thione
    images/download/thumbnails/1806797/6.png images/download/thumbnails/1806797/6.png images/download/thumbnails/1806797/6_d.png