Preparation background and overview of 2-(methyl)amino-5-borate
2-(Methyl)amino-5-borate is a pharmaceutical intermediate that can be prepared through a two-step reaction using 5-bromo-2-chloro-pyrimidine as the starting material.
Preparation of 2-(methyl)amino-5-borate
Preparation of 2-(methyl)amino-5-borate Preparation of 5-bromo-N-methyl-pyrimidine-2-amine
Dissolve 5-bromo-2-chloro-pyrimidine (1.93g, 10mmol) in 14mL of methylamine, microwave at 130°C, and stir for 40 minutes. The reaction solution of tetrahydrofuran was concentrated under reduced pressure, 20 mL of water and 20 mL of methylene chloride were added, and the liquids were extracted and separated. The aqueous phase was extracted with methylene chloride (10 mL of methoxypyridine 3), the organic phases were combined, and washed with saturated sodium chloride solution ( 10mL×2), dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain the crude title product 5-bromo-N-methyl-pyrimidine-2-amine (1.20g, white solid). The product was directly processed without purification. Next reaction. MS m/z(ESI): 189.9[M+1]
Preparation of 2-(methyl)amino-5-borate Preparation of 2-(methyl)amino-5-borate
Crude 5-bromo-N-methyl-pyrimidine-2-amine (1.20g, 6.38mmol), diboron divalerate (2.40g, 9.60mmol), 1,1′-bis(diphenyl Phosphorus) Ferrocene] Palladium dichloride (260 mg, 0.32 mmol) and potassium acetate (1.57 g, 16 mmol) were dissolved in 20 mL of dioxane, heated to 115°C, and stirred for 16 hours. Cool to room temperature, filter, and the filtrate is concentrated under reduced pressure. The residue obtained is purified by silica gel column chromatography with eluent system B to obtain 2-(methyl)amino-5-borate (1.30 g, white solid). Rate: 86.6%. MS m/z(ESI): 236.1[M+1]
