Insecticidal 4-pyridyl or 4-quinolyl carbamate derivs. - prepd. by reacting 4-hydroxy cpd. with carbamoyl halide using ammonia as hydrogen halide acceptor

摘要

In the prodn. of 4-pyridyl carbamates of formula (I) by reaction of a 4-pyridone of formula (IIa) or its tautomer (IIb) with a halide of formula (III) in the presence of a hydrogen halide acceptor at elevated temp., ammonia is used as the hydrogen halide acceptor and the reaction is carried out at 80-150, pref. 90-110 degrees C: Hal-CO-NR5R6 (III) In the formula R1 is H, 1-3C alkyl or phenyl; R2 is H or 1-3C alkyl; R3 is H and R4 is H or 1-3C alkyl, or R3+R4 = -CHA-CHB-CHC-CH2- in which A and C are H, 1-3C alkyl, 1-3C alkoxy or F, B is H or CF3, and the C-atom carrying A is attached to the 2-position of the pyridine ring; R5 and R6 are CH3 or C2H5; and Hal is Cl or Br. (I) are systemically active insecticides (cf. DT2361438).