Facile synthesis and nitration of cis-syn-cis-2,6-dioxodecahydro-1H,5H-diimidazo[4,5-b:4',5'-e]pyrazine
摘要:
The title ring system was synthesized for the first time by acid-promoted condensation of ureas with 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine. Nitrosation and nitration of the polycycle occurs first at the piperazine nitrogens. Successive further nitration leads to tetra-, penta-, and hexanitro derivatives. X-ray crystallographic analysis of the tetra- and hexanitro derivatives established the cis-syn-cis configuration and an all-axial conformation for this ring system. Possible reasons for the stereoselectivity of the condensation reaction are discussed.
Facile synthesis and nitration of cis-syn-cis-2,6-dioxodecahydro-1H,5H-diimidazo[4,5-b:4',5'-e]pyrazine
摘要:
The title ring system was synthesized for the first time by acid-promoted condensation of ureas with 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine. Nitrosation and nitration of the polycycle occurs first at the piperazine nitrogens. Successive further nitration leads to tetra-, penta-, and hexanitro derivatives. X-ray crystallographic analysis of the tetra- and hexanitro derivatives established the cis-syn-cis configuration and an all-axial conformation for this ring system. Possible reasons for the stereoselectivity of the condensation reaction are discussed.