Studies on Synthesis and Fungicidal Activities of Asymmetric Phosphoro(-no)thioates Containing Substituted Pyridine

As starting materials, Na salt of O,O-diethyldithiophosphoric acid and O,O-diethyl thiophosphorochloridate via esterification and dealkylation give O ethyl ammoniumdithio-or thiophosphates, which are treated with 2-chloro-5-chloromethylpyridine to give 2a～2c . O-ethylthiophosphorodichloridate and phenylthiophosphorodichloride react with a substituted phenol or methylamine and then with 2-chloro-5-hydroxymethylpyridine forming 2d～2k and 2m～2u . O-ethyl S propyldithiophosphorochloridate, O-ethylthiophosphorodichloridate and phenylthiophosphonodichloride react with 2-chloro-5-hydroxymethylpyri dine to afford 2l, 2v and 2w, respectively. In this way, twenty-three new title compounds 2 were prepared. The bioassay results showed that some of the title compounds possess a satisfactory or excellent fungicidal activity towards the R. solani(Palo) and P. oryzae fungus at mass fraction 5.0×10-5 ( in vitro ) or 5.0×10-4 ( in vitro ), but they have non or only lower fungicidal activity towards other seven plant fungi.