The synthesis of a 1, 5-diphenyl perhydro-pyrazolo-1, 2-a] pyrazole (IV) (m. p. = 170–171°) by LiAlH4-reduction of its 3, 7-dioxo derivative Va, one of the stereoisomers of V, is described. Va was obtained in small yield by the reaction of cinnamic acid with its hydrazide or with hydrazine. It proved to be identical with the compound obtained previously by interaction of cinnamic acid hydrazide with iodine which in the literature erroneously had been described as N, N′-dicinnamoyl hydrazine. This hydrazine now was obtained by bis-acylation of hydrazine with cinnamoyl chloride. In Va the extremely low NMR. absorption of the tertiary protons at ρ = 4,6 ppm is probably due to the spatial grouping with the proton situated in the deshielding region of the carbonyl group. Previously, another tertiary proton with a very low NMR. absorption at ρ = 4,85 ppm has been observed in the «bisimide M», the main criss-cross addition product of one mole benzaldazine and two moles of N-(n-butyl)-maleinimide. A stereostructure for bisimide M is now proposed, which is a hybrid between those of the bisimides L and H.
