PHOTO-CHEMICAL DECOMPOSITION OF 1,4-BENZODIAZEPINES - CHLORDIAZEPOXIDE

Irradiation of 7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine-4-oxide(I, chlordiazepoxido; the active compound of Librium Roche) with UV light provides a mixture of 1-benzoyl-7-chloro-1,2-dmydro-3-methylaminoquinoxalme(III) and 9-chloro-5-methylamino-2-phenyl-4H-benzo[g]-1,3,6-oxadiazocine(IV), while 7-chloro-2-methyl-amino-4,5-epoxy-4,5-dihydro-5-phenyl-3H-1,4-benzodiazepine(II, oxaziridine) is isolated as an intermediate. The quinoxaline and benzoxadiazocine derivatives (the photoisomers III and IV) decompose photochemically: the former to 2-methylamino-6-chloroquinoxaline(V), 2-methylammo-5-benzoyl-6-chloroquinoxaline(VI) and 2-methylamino-3-phenyl-6-chloroquinoxaline(VII), and the latter to 9-hydroxy-7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine(VIII). © 1979.