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Photochemische und thermische Erzeugung von Thiocarbonylyliden aus 2,5‐Dihydro‐1,3,4‐thiadiazolen
Author(s) -
Mloston Grzegorz,
Romanski Jaroslaw,
Schmidt Christiane,
Reisenauer Hans Peter,
Maier Günther
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941271226
Subject(s) - chemistry , diazomethane , thermal decomposition , methylene , photodissociation , medicinal chemistry , fragmentation (computing) , decomposition , ylide , yield (engineering) , photochemistry , organic chemistry , computer science , operating system , materials science , metallurgy
Photochemical and Thermal Generation of Thiocarbonyl Ylides from 2,5‐Dihydro‐1,3,4‐thiadiazoles [*] Thermolysis of thiadiazolines 2a‐c yields the corresponding thiiranes 5a‐c exclusively. In contrast matrix photolysis in an organic glass at 77 K or in solid Ar at 10 K allows the detection of the thiocarbonyl ylides 3a‐c , which are characterized by intense UV maxima at λ ≈ 350 nm. The thiocarbonyl ylides are formed in a stepwise manner and not directly from the thiadiazolines by a simple elimination of N 2 . In the first step a fragmentation into the thioketones 6a‐c and diazomethane occurs, followed by the generation of methylene ( 8 ) from diazomethane ( 7 ). Addition of methylene to the thioketones 6a‐c finally leads to the ylides 3a‐c.