Similar
to efavirenze, rilpivirine hydrochloride is a diarylpyrimidine
(DAPY) compound, and the large-scale process synthesis begins
with commercially available 2-methylthio-4-pyrimidinone (193)
shown in the scheme.
Thioether 193 was condensed with neat 4-cyanoaniline (194) at
elevated temperature to afford diarylamine 195 in 77% yield. Subsequent
treatment of pyrimidone 195 with refluxing POCl3 provided
the corresponding chloride 196 in 77% yield.160,161 In the
presence of K2CO3, chloride 196 was treated with the (E)-cinnamonitrile
aniline 200 to give rilpivirine hydrochloride (XIX) in good
yield.158 Aniline 200 was prepared via a Heck reaction of commercially
available 4-iodo-2,6-dimethyl-benzeneamine (197) and
acrylonitrile (198) affording compound 199 as a 4:1 mixture of E/Z isomers. The distribution of E/Z olefins was increased to 98:2
by salt formation and recrystallization to ultimately provide pure
(E)-200 in 64% yield for two steps.