NOVELTY - Synthesizing (E)-3-(3-phenylsulfamoyl-phenyl)-acrylic acid methyl ester (belinostat) involves: esterifying meta-benzene sulfonic acid sodium salt in presence of esterifying agent to obtain sodium 3-(methoxycarbonyl)benzenesulfonate, followed by chlorinating, contacting with aniline, reducing, oxidizing and condensing with phosphoryl acetic acid trimethyl ester.    USE - For synthesizing (E)-3-(3-phenylsulfamoyl-phenyl)-acrylic acid methyl ester (belinostat) (claimed) which is useful for treating cancer.    ADVANTAGE - The method utilizes reagents which are cheap and easy to obtain, thus decreases the production cost; avoids the use of the fuming sulfuric acid and other dangerous reagents; and decreases the potential safety hazard and environmental pollution. Also the method has simple operation, and purifying step of the intermediate utilizes the recrystallization method, which avoids the wastage of time-and-energy column chromatography purification, also the state of the intermediate in each step is solid, which is easy to operate and detect, it is suitable for industrial production.    DETAILED DESCRIPTION - Synthesizing (E)-3-(3-phenylsulfamoyl-phenyl)-acrylic acid methyl ester (belinostat) involves: esterifying meta-benzene sulfonic acid sodium salt in presence of esterifying agent to obtain sodium 3-(methoxycarbonyl)benzenesulfonate (III); chlorinating the compound (III) using chlorination reagent to obtain 3-chlorosulfonyl-benzoic acid methyl ester (IV); contacting the compound (IV) with a solvent (s1) and acid-binging agent (preferably aniline) to obtain 3-phenylsulfamoyl-benzoic acid methyl ester (V); reducing the compound (V) using reducing agent to obtain compound 3-hydroxymethyl-N-phenyl-benzenesulfonamide (VI); oxidizing the compound (VI) using oxidant optionally in presence of solvent (s2) to obtain 3-formyl-N-phenyl-benzenesulfonamide (VII); and condensing the compound (VII) with phosphoryl acetic acid trimethyl ester optionally in presence of solvent (s4).