Study On The Synthesis Of 2,4,6,8,10-pentabenzyl-2,4,6,8,10-pentaaza[3,3,3] Propellane And Its Debenzylation

Propellanes is a kind of important organic compounds.This special fused tricyclic system has higher ring tension and density,which is present in many natural product and also important in use of high energy density materials.Especially pentaaza[3.3.3]propellane,has the characteristics of abundant ring-nitrogen atoms,good symmetry and compact frame,so that it has a higher formation enthalpy/detonation,which is suitable for the skeleton structure of the energetic compound.Currently the syntheses of aza[3.3.3]propellane derivatives are more complex,and only its derivative by N-H protected by benzyl group has been synthesized,and there is no report on the debenzylation.This thesis will modify the improvement synthesis of 3,7,9,11-tetraoxo-2,4,6,8,10-pentabenzyl-2,4,6,8,10-penta-aza[3.3.3]propellane,and further study on the subsequent reduction of carbonyl group and debenzylation.Firstly,mono benzyl derivative of 3,7,9,11-tetraoxo-2,4,6,8,10-pentaaza[3.3.3]propellane was modified synthesis by the bromination,condensation with urea,ammonolysis by benzylamine and intramolecular cyclization from diethyl tartrate as the raw material.Secondely,the mono benzyl derivative synthesized was full-benzylation with benzyl bromide to provide the 3,7,9,11-tetraoxo-2,4,6,8,10-pentabenzyl-2,4,6,8,10-pentaaza[3.3.3]propellane.The synthesis route of the fully substituted propellane carbonyl compound was improved,the reaction conditions were optimized,the reaction time was shortened,the separation and purification operation was simplified,and the yield of the total route was increased to 42%.Then,the carbonyl groups of pentabenzyl propellane was reduced by the hydrogenation in the catalyst of lithium aluminum hydride to afford 2,4,6,8,10-penta-benzyl-2,4,6,8,10-pentaaza[3.3.3]propellane.The reaction conditions,purification and separation methods were optimized,and the yield reached 85%..All synthetic intermediates were characterized by IR,MS,¹H NMR and ¹³C NMR.Finally,the palladium-carbon catalytic hydrogenation debenzlation was preliminarily studied,and the crude examination showed that the conversion of the monobenzyl group was possible,but the exact structure needs further study.