3-chloro-3-phenyldiazirine

3-chloro-3-phenyldiazirine is a stable cyclic isomer of chlorodiazomethane; excellent source of chlorocarbene following thermolysis or photolysis^[1].

3-chloro-3-phenyldiazirine is prepared by treatment of benzamidine hydrochloride with NaOCl (eq 1).

3-chloro-3-phenyldiazirine can be stored in the dark at 0-10 °C for several weeks under Ar without decomposition; solutions of the reagent have not been known to detonate, although more volatile chlorodiazirines, e.g. methylchlorodiazirine, are prone to explosion and are shock sensitive; explosions have occurred on warming to rt after storage at 77 K. Extreme care is required during cold trap procedures when solid diazirine is present; in GC, diazirine must never be injected neat (the high temperature at the injector block will lead to an explosion). Always take precautions (e.g. safety shields) when working with diazirines.