(1S)-1-(3-Ethoxy-4-methoxy-phenyl)-2-methanesulfonyl-ethylamine

This specific chiral amine intermediate, often used as its N-acetyl-L-leucine salt, is a key building block to form the final active pharmaceutical ingredient (API). The compound (1S)-1-(3-Ethoxy-4-methoxy-phenyl)-2-methanesulfonyl-ethylamine is a crucial intermediate in the synthesis of Apremilast, a phosphodiesterase 4 (PDE4) inhibitor used to treat conditions like psoriatic arthritis and plaque psoriasis, working by modulating inflammatory responses.