The chemistry of bicyclic bisureas 1. Synthesis of 2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones and 2,4,6-8-tetraazabicyclo[3.3.1]nonane-3,7-diones by the reaction of ureas with α- and β-dicarbonyl compounds

1. The monooximes of alkyl- and aryl-α-dicarbonyl compounds gave 2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione only with the unsubstituted urea. 2. The most favorable conditions for the preparation of tetra-N-methyl derivatives of 2,4,6,8-tetraaza-bieyclo[3.3.1]nonane-3,7-diones by the condensation of N,N'-dimethylurea with malonic aldehyde tetraacetal and its substituted derivatives were established.