TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The organic solvent is chosen from methylene dichloride, tetrahydrofuran, dimethylformamide (DMF), glycol dimethyl ether, 1-dichloroethane, 2,6-dimethylpyrazine (DMP), methanol, ethanol, petroleum ether, n-hexane or diethyl ether, preferably methanol solvent. The organic alkali is chosen from imidazole, triethylamine, diisopropylethylamine, piperidine, dimethyl pyridine, lithium hexamethyldisilazane (LiHMDS), sodium hexamethyldisilazide (NaHMDS), potassium hexamethyldisilazane (KHMDS), N-methyl morpholine, diazabicyclooctane (DABCO), tetrabutyl ammonium fluoride or pyridine. The condensing agent is chosen from dicyclohexylcarbodiimide (DCC), carbodiimide hydrochloride (EDC), histone acetyltransferase (HATU), 1-hydroxy-7-azabenzotriazole (HOAt), 1-Hydroxybenzotriazole (HOBt), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate or Benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP)(RTM: Peptide coupling reagent). The acid is chosen from trifluoroacetic acid, hydrochloric acid, sulfuric acid or nitric acid. Preferred Process: The method for synthesizing histone deacetylase inhibitor involves mixing 3-methyl-pent-1-en-2-ol compound, threonine methyl ester, condensing agent in organic alkali at 0 degrees C, where the mol ratio of 3-methyl-pent-1-en-2-ol compound, threonine methyl ester, condensing agent in organic alkali solution is 1.0: 1.0-2: 1.0-5: 1.0-5. The reaction condensing agent is EDCI, and organic alkali is diisopropylethylamine. The obtained substituted butyric acid methyl ester compound of formula (I) is mixed with valine, condensing agent and organic alkali at 0 degrees C in the mol ratio of 1.0:1.0-2:1.0-5:1.0-5. The obtained substituted hydroxy butyric acid methyl ester compound of formula (II) is mixed with p-methanesulfonyl chloride and the organic alkali at 0 degrees C in the mol ratio of 1.0:1.0-2:1.0-10, where the reaction organic alkali is triethylamine and DABCO. The obtained obtain substituted butyramide compound of formula (III) is mixed with inorganic alkali mol ratio of 1.0:1.0-5 at 0 degrees C, where the reaction inorganic alkali is lithium hydroxide. The obtained substituted butanoic acid compound of formula (IV) is subjected to methyl esterification with L-malic acid, mixed with sodium borohydride and acetic acid in the mol ratio of 1.0: 1.0-1.3: 1.0-1.3, treated with inert gas at 0 degrees C, where the reaction organic solvent is tetrahydrofuran and the inert gas is argon. The obtained substituted pentanone compound of formula (V) is mixed with tertbutyldimethylsilyl chloride and organic alkali in the mol ratio of 1.0: 2.0-3.0: 2.0-3.0, where the reaction organic alkali is iminazole. The obtained substituted hexanone compound of formula (VI) is mixed with inorganic alkali in the mol ratio of 1.0: 1.0-1.5, where the inorganic alkali is potassium hydroxide or lithium hydroxide. The compound acid, the trimethoxy silane, the condensing agent and the organic alkali are mixed in the mol ratio of 1.0: 1.05: 1.0-5: 1.0-5, treated with inert gas, where the condensing agent is DCC, the organic alkali is DMAP, and inert gas is argon. The obtained 4-Hydroxy-3-methyl-butyric acid 2-trimethylsilanyl-ethyl ester compound of formula (VIII) is mixed with camphor sulfonic acid in the mol ratio of 1.0: 0.05-0.5 below -40-0 degrees C. The compound 12, compound 13, organic alkali and the oxidizing agent are mixed in the mol ratio of 1.0: 1.0-2.0: 1.0-3: 2.0-10 at 25-100 degrees C, where the organic alkali is triethylamine, and the oxidizing agent is p-methanesulfonyl chloride. The compound 20 is mixed with acid and the organic alkali in the mol ratio of 1.0: 1.0-10: 1.0-10 at 0 degrees C, where the acid is trifluoroacetic acid, and the organic alkali is tertbutyldimethylsilyl chloride. The macrocyclic precursor compound, the condensing agent and the organic alkali are mixed in the mol ratio of 1.0: 1.020: 1.0-20, treated with inert gas at 0 degrees C, where the organic solvent is dimethyl.