Reaction of N,N‐dimethylazidochloromethyleniminium chloride (azidophosgeniminium chloride) with 1,3‐dimethyl‐4‐aminouracils. A new “one pot” synthesis of 3‐aryl‐(and 3‐alkyl)‐4,6‐dimethyl‐5,7‐dioxo‐1,2,3‐triazolo[4,5‐d]pyrimidines (8‐azatheophyllines) via a diazo group transfer process

N,N ‐Dimethylazidochloromethyleniminium chloride (azidophosgeniminium chloride) ( 1 ) reacts by diazo group transfer with 1,3‐dimethyl‐4‐aryl‐(and alkyl)aminouracils 4 to give, under mild “one pot” reaction conditions, a very good yield of 3‐aryl‐(and 3‐alkyl)‐4,6‐dimethyl‐5,7‐dioxo‐1,2,3‐triazolo[4,5‐ d ]pyrimidines (8‐azatheophyllines) 8 . That reaction proceeds, very likely, through formation of non‐isolated 4‐imino‐5‐diazouracils 6 .