2-(Methyl-d3-sulfonyl)-ethan-1,1,2,2-d4-amine is an intermediate used in the synthesis of Lapatinib-d7 Dihydrochloride (L175807), which is a labeled Lapatinib (L175800), a reversible dual inhibitor of ErbB1 and ErbB2 tyrosine kinases. Antineoplastic.