1,4-Bis(diphenylphosphino)butane → Ethyl 6-amino-2-chloro-5-methoxypyrimidine-4-carboxylate

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Reaction Conditions

Reaction Steps

2,6-Dichloro-5-methoxypyrimidin-4-ylamine (5.0 g, 26 mmol) was combined in 75 mL absolute ethanol with sodium acetate (2.1 g, 26 mmol), palladium acetate (280 mg, 0.91 mmol) and DPPB (1.1 g, 2.6 mmol) in a 300 mL stirred pressure reactor. The reactor was purged and pressurized to 300 psi with carbon monoxide, and heated at 110° C. for 7 h. The volatiles were removed under vacuum and the residue was taken up in ethyl acetate and water. The aqueous phase was extracted with an additional ethyl acetate; and the combined extracts were washed with brine, dried and evaporated. The residue was purified by flash chromatography on silica gel (0-30% ethyl acetate gradient in hexanes) to give the title compound (1.4 g, 23% yield): mp 118-119° C. 1H NMR (CDCl3) δ 6.18 (br s, 2H), 4.45 (q, 2H), 3.91 (s, 3H), 1.42 (t, 3H).

Provenance & Evidence