p-Toluenesulfonic acid → methyl 7-[[(7R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-7H-pteridin-2-yl]amino]-2,2-dimethyl-3H-benzofuran-4-carboxylate

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Reaction Steps

Methyl 7-amino-2,2-dimethyl-3H-benzofuran-4-carboxylate 4d (770 mg, 3.48 mmol) was dissolved in 20 mL of 1,3-dimethyl-butanol followed by the addition of (7R)-2-chloro-8-cyclopentyl-7-ethyl-5-methyl-5H-pteridin-6-one 1o (1.23 g, 4.18 mmol) and p-toluenesulfonic acid (1.06 g, 5.57 mmol) successively. The reaction solution was heated to reflux for 2 hours with stirring. The resulting solution was added with 50 mL of saturated sodium bicarbonate solution, extracted with ethyl acetate (50 mL×3). The combined organic phase was washed with water (30 mL), saturated sodium chloride solution (20 mL) successively and dried over anhydrous magnesium sulfate. The filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound methyl 7-[[(7R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-7H-pteridin-2-yl]amino]-2,2-dimethyl-3H-benzofuran-4-carboxylate 4e (1.78 g, yield: 100%) as a light yellow solid.

Provenance & Evidence