Pyridine Derivatives as Insecticides. Part 3. Synthesis, Crystal Structure, and Toxicological Evaluation of Some New Partially Hydrogenated Isoquinolines against (, 1887).

Three new series of isoquinolines, that is, 7-acetyl-3-acetonylsulfanyl-8-aryl-1,6-dimethyl-6-hydroxy-5,6,7,8-tetrahydroisoquinoline-4-carbonitriles (-); 3-acetonylsulfanyl-8-aryl-1,6-dimethyl-7,8-dihydroisoquinoline-4-carbonitriles (-); and 7-acetyl-8-aryl-1,6-dimethyl-3-ethylsulfanyl-7,8-dihydroisoquinoline-4-carbo-nitriles (,) were carefully synthesized. Also, pyrazoloisoquinoline was used as a precursor for synthesis of 7-ethylsulfanyl-4-phenyl-1-thiocarbamoyl-3,5,9a-trimethyl-3a,4,9,9a-tetrahydro-1-pyrazolo[3,4-g]isoquinoline-8-carbonitrile (); 7-benzyl-sulfanyl-4-phenyl-1-thiocarbamoyl-3,5,9a-trimethyl-3a,4,9,9a-tetrahydro-1-pyrazolo[3,4-]isoquinoline-8-carbonitrile (); and 7-ethylsulfanyl-1-(4-oxo-4,5-dihydrothiazol-2-yl)-4-phenyl-3,5,9a-trimethyl-3a,4,9,9a-tetrahydro-1-pyrazolo[3,4-]isoquinoline-8-carbonitrile (). Moreover, the crystal structures of two representative compounds were determined. Eleven new compounds , , , , , , , , , , and were screneed for their toxicological activity against nymphs and adults of by using acetamprid, as a reference. After 24 h of treatment, the bioefficacy results indicate that all tested isoquinolines exhibit toxicological activity that varied from very high to low against nymphs and adults of , some compounds showing activity near to that of acetampirid and only one compound which possesses higher activity against nymphs and adults of than that of acetampirid itself.