Photochemical activity of 7-nitro-1,4-benzodiazepines
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The photochemical activity of nitrazepam, clonazepam and flunitrazepam has been investigated. These closely structurally related compounds decompose photochemically in an oxygen-poor medium, resulting in photoreductive dimerisation and photoreduction of the nitro-group to successively the nitroso, the hydroxylamino and finally the amino analogue of the nitro-compound. The photoreductive dimerisation compound is a result of a coupling reaction between the respective nitroso and hydroxylamino derivatives.
In an oxygen-rich medium, however, the 7-nitro-1,4-benzodiazepines are relatively photostable. It appears that the quenching of excited clonazepam and nitrazepam leads exclusively to the formation of singlet molecular oxygen, while in the case of flunitrazepam, beside singlet molecular oxygen, also another reactive oxygen-dependent species is formed.
In addition the photochemical activity of methylnitrazepam, methylclonazepam and desmethylflunitrazepam has been investigated. It appears that a relationship exists between the 7-nitro group in the 1,4-benzodiazepine nucleus and the photochemical behaviour.
KeywordsMethylene Blue Clonazepam Nitroso Flunitrazepam Nitrazepam
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