Abstract :
4-Substituted-1,2,4-triazoline-3,5-diones are very reactive dienophiles (1-12) as well as enophiles (6-12). The chemistry of triazolinediones,except for their enhanced reactivity due to the cis configuration,is like that of diethyazodicarboxylate and other a-carbonylazo compound (13-22). It has been reported that 4-phenyl-1,2,4-triazoline-3,5-done, lais 1000 times more reactive in the Diels-Alder reaction with 2-chlorobutadiene than tetracyanoethylene (23)and 2000 times more reactive than maleic anhydride (24).4-Methyl-1,2,4-triazoline-3,4-triazoline-3,4-dione 1b has been reported to be at least 30,000 times more reactive toward cyclohexene than its open-chain analog, diethylazodicarboxylate (6).
