Dipicryl-l,3,4-oxadiazole

Dipicryl-l,3,4-oxadiazole has been described as an initiating explosive, 2,5-dimethyl-l,3,4-oxadiazole has been used to extract aromatic hydrocarbons from mixtures with alkanes. The use of 4,4 -carbonyl-bis(2-phenyl-5-oxo-l,3,4-oxadiazole) as a blowing agent for foaming thermoplastic compositions (e.g., polycarbonates) has been described < 1996CHEC-II(4)268>. 

The dehydration of A,A -diacylhydrazines is a standard method for the formation of the 1,3,4-oxadiazole ring. 2,5-Dipicryl-l,3,4-oxadiazole (DPO) (19) is synthesized by treating 2,4,6-trinitrobenzoic acid (17) with phosphorous pentachloride, followed by treatment with hydrazine to give the A, A -diacylhydrazine (18) which undergoes dehydration on further reaction with phosphorous pentachloride in 1,2-dichloroethane. DPO exhibits high thermal stability but is very sensitive to impact and shock, making it useful in detonation transfer compositions. 

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