Lithium Hexamethyldisilazide → 3-(2-methoxyethoxy)-1-trityl-1H-pyrazolo[4,3-c]pyridin-6-amine

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Reaction Conditions

Reaction Steps

6-chloro-3-(2-methoxyethoxy)-1-trityl-1H-pyrazolo[4,3-c]pyridine (500 mg, 1.064 mmol) and SPHOS Palladacycle (162 mg, 0.213 mmol) were mixed in a pressure release vial, degassed and backfilled with Nitrogen (3×), tetrahydrofuran (8 mL) was added, followed by the addition of lithium bis(trimethylsilyl)amide (1M) (2.128 mL, 2.128 mmol), the resultant mixture was degassed and backfilled with nitrogen (3×), and heated up to 60° C. for overnight. Hydrochloric acid 1M (2 mL) was added, and the mixture was stirred at room temperature for 2 h, the mixture was basified with aqueous sodium hydroxide (1M, ˜4 mL) to pH 9, and the mixture was extracted with ethyl acetate (2×10 mL). The combined organic fractions were washed with brine (saturated, lx 10 mL), dried (MgSO4), filtered and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel (40 g), eluting with EtOAc/isohexane=50%-100% to give 3-(2-methoxyethoxy)-1-trityl-1H-pyrazolo[4,3-c]pyridin-6-amine (32B, 432 mg, 0.959 mmol, 90% yield) as a brown solid. MS: [M+H]+ m/z 451.

Provenance & Evidence