Unexpected Formation of [(∆ ³-Piperideino)pyrimidino]-14-crown-4 Ethers in a Petrenko-Kritschenko Type Condensation

Two novel aza-14-crown-4 ether derivatives bearing fused (∆ ³ -piperideino)[2,3-e]pyrimidine moieties as subunits were unexpectedly obtained as major products of a modified Petrenko-Kritschenko type cascade condensation of 1-benzyl-4-ethoxycarbonylpiperidin-3-one with 1,5-bis(2-formylphenoxy)-3-oxapentane and ammonium acetate. X-ray structure study was performed to determine the structure of the compounds.