The invention discloses a preparation method of an
optically active pydiflumetofen intermediate, which comprises the following specific operation processes: dissolving (+ / -)-O-methyl-N-[1-methyl-2-(2, 4, 6-trichlorophenyl)-ethyl]-
hydroxylamine by using an
organic solvent, adding into 100mM of PBS (
Phosphate Buffer Solution) with pH (Potential of
Hydrogen) of 7.5, then adding
monoamine oxidase and a chemical
reducing agent, continuously introducing
oxygen, reacting for 2-3 hours at the temperature of 50-60 DEG C, and finally adding a catalyst, thereby obtaining the
optically active pydiflumetofen intermediate. The preparation method comprises the following steps of: stirring and reacting until the reaction is complete,
quenching the reaction solution by using a
sodium hydroxide solution, filtering the reaction solution by using diatomite to remove the quenched precipitate, extracting the filtrate for three times by using an
organic solvent, merging the extract liquor, washing with water,
drying by using
anhydrous Na2SO4, and concentrating under reduced pressure to obtain the (S)-O-methyl-N-[1-methyl-2-(2, 4, 6-trichlorophenyl)-ethyl]-
hydroxylamine. The method has the advantages of being simple in operation process, low in cost,
environmentally friendly, capable of saving energy and the like, deracemization of the high-concentration pydiflumetofen intermediate amine can be achieved, the yield is high, and the optical purity of the product is high.