Synthesis, Crystal Structure and Biological Activity of 6-Alkyl-7-imino-3-phenyl-2-thioxo-2,3,6,7-tetrahydrothiazolo[4,5-d]pyrimidines

Ten novel thiazolo[4,5-d]pyrimidines 6a similar to 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 by H-1 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 compounds showed moderate fungicidal or herbicidal activities.