反应详情

A mixture of (trans)-3-(2,3-dihydrobenzodioxin-5-yl)propenoic acid (9.83 g, 47.7 mmol), thionyl chloride (20 mL), and CH2Cl2 (75 mL) was heated to reflux for 1 hr, and then concentrated in vacuo to give a yellow-green solid. This material was dissolved in ethyl acetate (75 mL), and a solution of N,O-dimethylhydroxylamine hydrochloride (9.5 g) in saturated Na2CO3 (100 mL) was added with stirring. The mixture was stirred for 90 min and then diluted with water and ethyl acetate. The ethyl acetate layer was separated and washed twice with water and twice with saturated Na2CO3. The ethyl acetate layer was concentrated in vacuo to give a brown oil. This crude product was chromatographed on silica gel using 1:1 ethyl acetate/methylene chloride as the eluent to give a clear oil that crystallized upon standing (11.1 g, 93.1%).

1. temperaturewas heated
2. temperatureto reflux for 1 hr
3. concentrationconcentrated in vacuo
4. customto give a yellow-green solid
5. stirringThe mixture was stirred for 90 min
6. customThe ethyl acetate layer was separated
7. washwashed twice with water and twice with saturated Na2CO3
8. concentrationThe ethyl acetate layer was concentrated in vacuo
9. customto give a brown oil
10. customThis crude product was chromatographed on silica gel using 1:1 ethyl acetate/methylene chloride as the eluent
11. customto give a clear oil that
12. customcrystallized