The invention discloses a
ribociclib intermediate preparation method, which comprises: (1) mixing a compound I,
iodine, a catalyst A and a
solvent A, heating to a temperature of 70-80 DEG C, and carrying out a heat preservation reaction for 5-6 h to generate a compound II; (2) mixing the compound II,
phosphorus oxychloride and alkali B, and reacting to generate a compound III; (3) dissolving the compound III and alkali C in a
solvent C, cooling to-10-0 DEG C, dropwise adding a
mixed solution of cyclopentylamine and the
solvent C, and reacting for 1-5 hours after dropwise adding to obtain a compound IV; (4) under the protection of
inert gas, adding the compound IV,
propargyl alcohol, a
palladium catalyst, alkali D, a ligand and an activating agent into a solvent D, and carrying out
Sonogashira coupling reaction for 5-10 hours to obtain a compound V; the method is mild in reaction condition, high in reaction yield, high in
operability, low in production cost, green,
environmentally friendly and suitable for large-scale industrial production.