Acetone → Ruxolitinib impurity 133

Participants

Reaction Conditions

Reaction Steps

A solution of racemic (4-(1-(2-Cyano-1-cyclopentylethyl)-1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl)methyl pivalate (20, 200 mg, 0.47 mmol) in a mixture of acetonitrile, tetrahydrofuran, and acetone (4 mL, 6:1:1) at room temperature was warmed to 50° C. before being treated with (+)-2,3-dibenzoyl-D-tartaric acid (16, 84 mg, 0.235 mmol, 0.5 equiv) in one portion. The resulting homogeneous solution was then stirred at 50° C. for 10 minutes before being cooled gradually to room temperature and stirred at room temperature for 23 hours. The solids were then collected by filtration, rinsed with a small volume of hexane, and dried under reduced pressure to afford (2S,3S)-2,3-bis(benzoyloxy)succinic acid-(R)-(4-(1-(2-cyano-1-cyclopentylethyl)-1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl)methyl pivalate (1:1; 22, 145 mg, 183 mg theoretical, 79.2% yield) as white crystals. The enantiomeric purity of the isolated salt was analyzed by chiral HPLC and found to be in a ratio of 87:13 favoring the desired R-enantiomer. For 22: C23H28N6O2 (MW, 420.51), LCMS (EI) m/e 421.4 (M++H).

Provenance & Evidence