N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
8.6 Heteroaromatics
389
Cinnoline, Phthalazine, Quinazoline, Quinoxaline
Fragmentation: Same as for the corresponding monocyclic heteroaromatics
pyridazine, pyrimidine, and pyrazine. Characteristic for pyridazine, cinnoline, and
phthalazine is the elimination of N 2 (Δm 28) and N 2 H · (Δm 29) from their alkyl
derivatives. Phthalazine loses HCN (Δm 27) twice.
Ion series: Aromatic hydrocarbon fragments, (C n H n , C n H n±1 ) and C n H n±1 N (m/z
39–41, 51–54, 63–67, 75–80, …).
Intensities: Dominant maximum for M +· or, if possible, for products of benzylictype cleavage.
Molecular ion: Strong, except when benzylic-type cleavage is possible. Odd mass
for odd number of N atoms in the molecule. No tendency to protonate. [M-1] + is
usually present and is strong in alkyl-substituted compounds.
References
[1] Q.N. Porter, Mass Spectrometry of Heterocyclic Compounds, 2nd ed.; Wiley:
New York, 1985.
[2] D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. III. Rearrangements involving the loss of small
neutral molecules, Chem. Rev. 1975, 75, 693.
[3] R. Spilker, H.-F. Grützmacher, Isomerization and fragmentation of methylfuran
ions and pyran ions in the gas phase, Org. Mass Spectrom. 1986, 21, 459.
[4] W. Riepe, M. Zander, Mass-spectrometric fragmentation behavior of thiophene
benzologs, Org. Mass Spectrom. 1979, 14, 455.
[5] H. Budzikiewicz, C. Djerassi, A.H. Jackson, G.W. Kenner, D.J. Newman, J.M.
Wilson, Mass spectra of monocyclic derivatives of pyrrole, J. Chem. Soc. 1964,
1949.
[6] W.M.A. Niessen, R.A. Correa C., Interpretation of MS-MS Mass Spectra of
Drugs and Pesticides, Wiley, Hoboken, 2017.
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
8.6 Heteroaromatics
389
Cinnoline, Phthalazine, Quinazoline, Quinoxaline
Fragmentation: Same as for the corresponding monocyclic heteroaromatics
pyridazine, pyrimidine, and pyrazine. Characteristic for pyridazine, cinnoline, and
phthalazine is the elimination of N 2 (Δm 28) and N 2 H · (Δm 29) from their alkyl
derivatives. Phthalazine loses HCN (Δm 27) twice.
Ion series: Aromatic hydrocarbon fragments, (C n H n , C n H n±1 ) and C n H n±1 N (m/z
39–41, 51–54, 63–67, 75–80, …).
Intensities: Dominant maximum for M +· or, if possible, for products of benzylictype cleavage.
Molecular ion: Strong, except when benzylic-type cleavage is possible. Odd mass
for odd number of N atoms in the molecule. No tendency to protonate. [M-1] + is
usually present and is strong in alkyl-substituted compounds.
References
[1] Q.N. Porter, Mass Spectrometry of Heterocyclic Compounds, 2nd ed.; Wiley:
New York, 1985.
[2] D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. III. Rearrangements involving the loss of small
neutral molecules, Chem. Rev. 1975, 75, 693.
[3] R. Spilker, H.-F. Grützmacher, Isomerization and fragmentation of methylfuran
ions and pyran ions in the gas phase, Org. Mass Spectrom. 1986, 21, 459.
[4] W. Riepe, M. Zander, Mass-spectrometric fragmentation behavior of thiophene
benzologs, Org. Mass Spectrom. 1979, 14, 455.
[5] H. Budzikiewicz, C. Djerassi, A.H. Jackson, G.W. Kenner, D.J. Newman, J.M.
Wilson, Mass spectra of monocyclic derivatives of pyrrole, J. Chem. Soc. 1964,
1949.
[6] W.M.A. Niessen, R.A. Correa C., Interpretation of MS-MS Mass Spectra of
Drugs and Pesticides, Wiley, Hoboken, 2017.