Dense compounds of C, H, N, and O atoms: Nitramine derivatives of diimino‐ and dioxodecahydro‐1 h,5h‐diimidazo‐[4,5‐b:4′,5′‐e]pyrazine

Abstract

AbstractGuanidine condensed with 1,4‐diformyl‐2,3,5,6‐tetrahydroxypiperazine 1 to give 2,6‐diiminodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 3 isolated as the tetrahydrochloride salt. nitric acid (100%) at −40°C converted the bisguanidine 3 to 2,6‐dinitrimino‐4,8‐dinitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]‐ pyrazine 8 isolated as a dihydrate, whereas nitration by nitronium tetrafluoroborate at 0° to 25°C afforded 2,6‐diimino‐4,8‐dinitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 9 isolate as the monohydrated bistetrafluoroborate salt, and treatmetn with nitric acid (100%) and acetic anhydride or phosphorus pentoxide converted the bisguanidine 3 to 2,6‐dioxo‐1,3,4,5,7,8‐hexanitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 4, also obtained from the tetra N‐nitro compound 8 · 2 H2O and from the dinitramine 9 · 2 BHF4 · H2O after similar treatment. The cis‐syn‐cis‐ configuration of the tricyclic bisurea 4 and bisguanidine 9 was confirmed by X‐ray crys‐tallographic analysis. Nitrosation by nitrous acid or by dinitrogen tetroxide converted the bisguanidine 3 to a hydrated 2,6‐dinitrosimino‐4,8‐dinitrosodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐]pyrazine 10 · 2.5 H2O, whereas treatment with nitrosonium tetrafluo‐roborate afforded the bistetrafluoroborate salt of 4,8‐dinitroso derivative 11 · 2 BHF 4. The nitrosamines 10 and 11 were converted to the tetranitro compound 8 · 2 H2O on treatment with nitric acid (100%) at −40°C. Treatmnt with fluoroboric acid etherate in acetonitrile converted nitroimino groups in compound 8 · 2 H2O and nitrosimino groups in compound 10 · 2.5 H2O to imino groups in compounds 9 · 2 BHF2 · H2O and 11 · 2 HBF4 respectively.