Ten novel thiazolo[4,5-d]pyrimidines 6a∼6j have been synthesized by the reaction of 5-cyano-3-phenyl-2-thioxo-2,3-dihydro-4- ethoxymethylideneaminothiazole (5) with amines via intramolecular cyclization of formamidines. Their structures were characterized by1H NMR, IR spectra and elemental analysis, and the structure of 6i was further determined by an X-ray single crystal diffraction method. The preliminary bioassay indicated that some com...