Spectra of Simple Heterocyclic Molecules

The spectra of unsubstituted heterocyclic compounds are characterized by very intense peaks of the molecular ions. The elimination of one electron from their rich stock of 7r electrons requires only a very 

The spectrum of furan18 shows, besides the molecular ion peak (M+), a very pronounced peak of the cyclopropenylium ion [1] at mass 39. This is in accordance with the rather low aromatic character of furan in comparison with other heterocyclics, facilitating its 

18 Ions and fragments are put in square brackets [ ], while molecules are symbolized by parentheses ( ). 

The presence of the methyl groups causes a shift of the cyclopropenyl ion [1] of unsubstituted furan by 14 mass units (MU), to mass 53, because in this case a methylcyclopropenyl cation is produced. 

In a-substituted monomethylfurans (8), formyl [9] and acetyl [10] ions are formed together  

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C. Correlations between Mass Spectrum and Structure II. Mass Spectra of Simple Heterocyclic Molecules... 

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