Premium
Electron ionization mass spectra and crystal structures of some [1,2,4]triazolo[1,2‐ b ]‐ and [1,3,4]thiadiazolo[3,4‐ b ]phthalazines
Author(s) -
Joutsiniemi Karoliina,
Ahlgrén Markku,
Vainiotalo Pirjo,
Morgenstem Olaf,
Meusel Mario
Publication year - 1995
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570320148
Subject(s) - phthalazine , chemistry , mass spectrum , fragmentation (computing) , ring (chemistry) , crystallography , crystal structure , electron ionization , ion , ionization , medicinal chemistry , organic chemistry , computer science , operating system
The mass spectra of ten 1,3‐dithioxo[1,2,4]triazolo[1,2,‐ b ]phthalazines, five 3‐iminosubstituted 1‐thioxo‐[1,3,4]thiadiazolo[3,4‐ b ]phthalazines, three 3‐iminosubstituted‐1‐thioxo[1,2,4]triazolo[1,2‐ b ]phthalazines, and 1,3‐dithioxo‐5,10‐dihydro[1,3,4]thiadiazolo[3,4‐ b ]phthalazine were recorded under electron ionization. The fragmentation pathways were elucidated by metastable ion analysis and exact mass measurements. The changes in the ring‐system had little effect on the fragmentation mechanism, but the effect on peak intensities was considerable. The most important fragmentations began with the opening of the triazole ring. Substituents at nitrogen atoms also had a marked effect on the mass spectral behavior. The aryl substituents prompted a whole new fragmentation. The X‐ray crystal structure was determined for a few compounds. Two of the three structures of the 1,3‐dithioxo[1,2,4]triazolo[1,2‐ b ]phthalazines that were studied proved to be relatively planar, whereas the structure of 1,3‐dithioxo‐5,10‐dihydro[1,3,4]thiadiazolo[3,4‐ b ]phthalazine was considerably bent similarly to the 2‐(4‐chlorophenyl)‐1,3‐dithioxo‐2,3,5,10‐tetrahydro[1,2,4]triazolo[1,2‐ b ]‐phthalazine. The triazole and the thiadiazole rings had a strong double bond nature.