2,2,2-Trinitroethyl 4,4-dinitropentanoate has been made by the addition of 1,1-dinitroethane to methyl acrylate, hydrolysis of the methyl ester and esterification of the resulting acid with trinitroethanol. The compound is a castable high explosive, m.p. 92.5 deg. C; crystal density 1.60; impact sensitivity 70 cm; hot bar ignition temperature 297 deg. C; vacuum stability 1.1 cc of gas/g/48 hours at 100 deg. C.