Photochemistry of aromatic compounds. Fragmentation reactions originating in a photo-induced electron transfer in solution

Photochemistry of the carbon-nitrogen double bond

“…In sensitizers, a notable increase in N-N bond cleavage has been observed,250 thus supporting a singlet pathway for the formation of the diazepine and a triplet pathway for the competing cleavage. No rearrangement is observed on irradiation of a series of 4-imino-1,2,4-triazolium ylides (158).257 Instead, N-N bond cleavage occurs resulting in a 1,2,4-triazole and a nitrene which can be trapped with methanol. Further evidence for nitrene intermediates in these reactions is provided by the photolysis of 161 in diethylamine.…”

Photodebromination of Bromothiophenes

“…The halides which have been studied include halobenzenes [1][2][3][4][5][6] , halonaphthalenes 3 - [7][8][9][10][11][12] , bromobiphenyls 13 , bromopyridines 14 - 15 , bromoquinolines and bromoisoquinolines 14~16 , and bromopyrimidines [17][18][19] . The considerable interest in the photochemistry of halothiophenes 20 prompts us to report our results obtained with bromothiophenes and representing a continuation of om previous work on the photodebromination of bromoquinolines and bromoisoquinolines 16 .…”