Potassium Phosphate, Tribasic → [(5S)-3-(5-Bromopyridin-2-yl)-4,5-dihydroisoxazol-5-yl]methyl butyrate

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Reaction Steps

Racemic [3-(5-bromopyridin-2-yl)-4,5-dihydroisoxazol-5-yl]methyl butyrate (Intermediate 9, 80 g, 0.244 mol) was dissolved in acetone (4 L), and 0.1 M potassium phosphate buffer (pH˜7) (4 L) was added with vigorous stirring to give a clear yellow solution. PS-lipase (1.45 g, Sigma cat no L-9156) was added and the mixture was gently stirred at ambient temp. for 42 hrs. The solution was divided into 3 equal volumes of ˜2.6 L and each was extracted with dichloromethane (2×1 L), the pooled organic phases were dried over sodium sulfate and evaporated. The unreacted [(5S)-3-(5-bromopyridin-2-yl)-4,5-dihydroisoxazol-5-yl]methyl butyrate was isolated via flash column chromatography (9:1 hexane:ethyl acetate) as a clear yellow oil, 36.4 g (45.5%).

Provenance & Evidence