Novel and Efficient Synthesis of Deuterium-Labeled Olopatadine-d6

A novel and highly efficient synthetic approach has been developed for the synthesis of deuterium-labeled olopatadine- d 6 using inexpensive and commercially available dimethyl sulfate- d 6 at the stage of alkylation of primary amine intermediate. The proposed synthetic path makes it possible to avoid the use of expensive labeled reagents such as dimethyl amine- d 6 used as labeled precursor in the traditional synthetic route. The structure of the obtained olapatadine- d 6 has been confirmed by 1 H NMR and mass spectral data.