Mesoionic purinone analogs. III. The synthesis and properties of mesoionic thiazolo[3,2‐a ] pyrimidine‐5,7‐diones

A number of mesoionic thiazolo[3,2‐ a ]pyrimidine‐5,7‐diones, isoconjugate mesoionic analogs of xanthinc, were prepared by the condensation of 2‐alkylaminothiazoles with bis(2,4,6‐trichloro‐phenyl)malonate esters. The ground state molecular properties and reactions of these compounds were found to be consistent with predictions based upon previous SCF molecular orbital treatments of the π‐systems of these analogs.