NOVELTY - Preparation of (S)-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylamine (I) involves condensing 3-ethoxy-4-methoxybenzoate with dimethyl sulfone in a solvent (A) in presence of nitrogen and strong base, obtaining 1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethanone (II), reacting resultant compound with chiral amine in solvent (B) in presence of acidic catalyst, obtaining 1-N-substituted-amino-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylene (III) and hydrogenating resultant compound.    USE - Preparation of (S)-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylamine used as intermediate for preparing apremilast (claimed).    ADVANTAGE - The method enables preparation of (S)-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylamine with high yield, by simple, economical and environmentally-friendly process.    DETAILED DESCRIPTION - Preparation of (S)-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylamine of formula (I) involves condensing 3-ethoxy-4-methoxybenzoate with dimethyl sulfone in a solvent (A) in presence of nitrogen and strong base, obtaining 1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethanone of formula (II), reacting resultant compound with chiral amine in solvent (B) in presence of acidic catalyst, obtaining 1-N-substituted-amino-1-(3-ethoxy-4-methoxy)phenyl-2-methanesulfonyl-ethylene of formula (III) and hydrogenating resultant compound. The strong base is solid sodium methoxide, sodium solid ethanol, potassium tert-butoxide and/or sodium hydride. The molar ratio of 3-ethoxy-4-methoxybenzoate, strong base and dimethyl sulfone is 1:1-3:1-10. The solvent (A) is chosen from n-hexane, cyclohexane, toluene, dimethylsulfoxide, tetrahydrofuran and 2-methyl-tetrahydrofuran. The solvent (B) is chosen from acetic acid, methanol, ethanol, propanol, cyclohexane, tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether, toluene and alkyl halide. The chiral amine is chosen from chiral amino aromatic amine, chiral amino fatty amine and chiral amino acid. An INDEPENDENT CLAIM is included for preparation of apremilast, which involves condensing compound (I) with 3-acetamidophthalic anhydride and optionally reacting with N-acetamido-L-leucine salt.