Nitrogen → tert-Butyl 4-(4-((4-chloro-5-(trifluoromethyl)pyrimidin-2-yl)amino)-3-methoxyphenyl)piperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

To a stirred chilled solution (0° C.) of 2,4-dichloro-5-(trifluromethyl)pyrimidine (0.800 g, 3.68 mmol) under a stream of dry N2 gas in 1:1 dichloroethane/tert-butanol (50 mL) was added a solution of zinc chloride (1 M in diethyl ether; 4.42 mL, 4.42 mmol). After 1 hour of stirring at 0° C., a solution of tert-butyl 4-(4-amino-3-methoxyphenyl)piperazine-1-carboxylate (I2) in 1:1 dichloroethane/tert-butanol (15 mL) (1.13 g, 3.68 mmol, 1 eq.) was added drop wise over 30 minutes followed by the drop wise addition of a solution of triethylamine (0.565 mL, 0.410 mmol, 1.1 eq.) in 1:1 dichloroethane/tert-butanol (5 mL) over 30 minutes. The resulting mixture was then stirred vigorously at room temperature for 18 hours. The volatiles were evaporated under reduced pressure and the residue then dried under high vacuum. Ethyl acetate and water were added and the aqueous layer was extracted with ethyl acetate (3×30 mL). The combined organic extracts were washed with water, brine, dried (magnesium sulfate), filtered and evaporated to give the crude product as a dark yellow foam. The crude product was purified by flash column chromatography on silica gel (0-20% ethyl acetate/petroleum ether) to yield the title compound (I3) (1.25 g, 69%) as a yellow solid; 1H NMR (300 MHz, CDCl3) δ 1.48 (s, 9H), 3.11 (t, 4H, J=5.2 Hz), 3.59 (t, 4H, J=5.0 Hz), 3.88 (s, 3H), 6.54 (s, 1H), 6.57 (d, 1H, J=9.4 Hz), 7.83 (s, 1H), 8.17 (d, 1H, J=8.5 Hz) and 8.53 (s, 1H). LCMS Method B: rt 9.24 min; m/z 488.3 [M+H]+.

Provenance & Evidence