The chemistry of carbazole. VI. On the formation of N‐ethylcarbazoles in the cadogan reaction

Reaction of 2′,6‐dimethyl‐2‐nitrobiphenyl with triethyl phosphite gave 4,5‐dimethyl‐9‐ethylcarbazole besides 4,5‐dimethylcarbazole. In this reaction, 4,5‐dimethylcarbazole was ethylated by triethyl N‐(2′,6‐dimethybiphenyl‐2‐yl)phosphorimidate and diethyl N‐(2′,6‐dimethylbiphenyl‐2‐yl)phosphoramidate, which arose from a nitrene‐intermediate and triethyl phosphite. Analogous ethylations of carbazole with other phosphorimidate and phosphoramidates were investigated.