Activation of the anticancer drug CCNU into a free radical intermediate via UV irradiation—An ESR study

A Critical Appraisal of the Evolution ofN-Nitrosoureas as Anticancer Drugs

“…Ultraviolet irradiation of BCNU ( 33 ) and CCNU ( 137b ) in benzene , caused the formation of free radical intermediates, and a stable nitroxyl radical 886 (Chart ) from CCNU was discovered 609 by EPR spectroscopy. The formation of the stable nitroxyl 853 from the corresponding piperidine under UV radiation increased considerably in the presence of CCNU .…”

“…Ultraviolet irradiation of BCNU ( 33 ) and CCNU ( 137b ) in benzene , caused the formation of free radical intermediates, and a stable nitroxyl radical 886 (Chart ) from CCNU was discovered 609 by EPR spectroscopy. The formation of the stable nitroxyl 853 from the corresponding piperidine under UV radiation increased considerably in the presence of CCNU . Therefore, a suggestion 609 was made that the CENU drugs, such as CCNU ( 137b ), can form stable nitroxyl radicals in situ which can act as photosensitizers and cause the production of more free radicals.…”

“…Therefore, a suggestion 609 was made that the CENU drugs, such as CCNU ( 137b ), can form stable nitroxyl radicals in situ which can act as photosensitizers and cause the production of more free radicals. As a result, various toxic oxygen species could be formed in vivo and these could contribute to the toxic side effects of CCNU …”