Hydrochloric Acid → Bortezomib

Beteiligte Stoffe

Reaktionsschritte

A 100 ml three neck round bottom flask was equipped with a stir bar, thermocouple and nitrogen inlet/outlet then charged with 5.0 g (10.4 mmol) of (2S)—N-[(1R)-1-(1,3,6,2-dioxazaborocan-2-yl)-3-methylbutyl]-3-phenyl-2-(pyrazin-2-ylformamido)propan-amide (i.e., boronic ester of Formula XI), 50 ml of methanol and 10.4 ml of 2N aqueous hydrochloric acid. The reaction was stirred at room temperature overnight before removing the solvent in vacuo at 40° C. The resulting residue was dissolved in 50 ml of ethyl acetate and washed with saturated sodium bicarbonate (1×50 mL) before once again concentrating the organic to dryness in vacuo. The residue was then triturated overnight at room temperature with 50 mL of pentane under nitrogen. The resulting free flowing solids were collected by vacuum filtration, washed with pentane (1×20 ml) then dried in a vacuum oven at 30° C. overnight to provide 3.29 g (8.56 mmol, 82.3%) of the title compound as a white solid. HPLC analysis indicated chemical purity >99.8 A % and a 93.5:6.5 ratio of diastereomers (i.e., 87% de).

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