An improved synthesis of 2-amino-5-[(4-chlorophenyl)thio]-4-morpholinopyrimidine (BW 394U) - A potential antisenility agent

This paper describes the synthesis of 2-amino-5-[(4-chlorophenyl)thio]-4-morpholinopyrimidine (BW 394U, compound 4), a potential antisenility agent. The key intermediates 3a/3b were obtained from an in situ-generated Vilsmeier-Haack reagent that simultaneously protected the 2-amino group prior to further manipulations. Displacement of the chloro group in 3a gave 4 in 40% yield and 4-dimethylamino analogue 5. However, displacement of 3b with morpholine followed by treatment with aqueous base gave 4 in 74% yield.