反应详情

[(5S)-3-(5-Bromopyridin-2-yl)-4,5-dihydroisoxazol-5-yl]methyl butyrate (Intermediate 10, 16.88 g, 0.051 mol) was dissolved in methanol (110 ml). 50% Aqueous sodium hydroxide (3.6 ml, 0.068 mol) was added. The solution was stirred at RT for 15 minutes, 1M HCl (75 ml) was added, followed by concentration in vacuo to ˜100 ml total volume. Water (˜50 ml) was added, and the white precipitate was collected and rinsed with water. The filtrate was extracted twice with ethyl acetate, the organic layers were pooled, dried over sodium sulfate and evaporated. The solid residue was collected and rinsed with 10:1 hexane:ethyl acetate, then combined with the initial precipitate before drying in vacuo to give the title compound as a white crystalline solid, 12.3 g (93%). Chiral HPLC analysis indicated <0.5% of the (−) isomer was present. [α]D=+139 (c=0.01 g/ml in methanol).

1. concentrationfollowed by concentration in vacuo to ˜100 ml total volume
2. additionWater (˜50 ml) was added
3. customthe white precipitate was collected
4. washrinsed with water
5. extractionThe filtrate was extracted twice with ethyl acetate
6. dry with materialdried over sodium sulfate
7. customevaporated
8. customThe solid residue was collected
9. washrinsed with 10:1 hexane
10. custombefore drying in vacuo