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Methyl 1-[3-(4-{[tert-butyl(dimethyl)silyl]oxy}phenyl)-5-hydroxy-4-phenyl-4,5-dihydroisoxazol-5-yl]cyclopropanecarboxylate

Compound C

Methyl 1-[3-(4-{[tert-butyl(dimethyl)silyl]oxy}phenyl)-5-hydroxy-4-phenyl-4,5-dihydroisoxazol-5-yl]cyclopropanecarboxylate

p-toluenesulfonic acid hydrate

→

1-{3-[4-(tert-Butyl-dimethyl-silanyloxy)-phenyl]-4-phenyl-isoxazol-5-yl}-cyclopropanecarboxylic acid methyl ester

용매

toluene

chloroform

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후처리

1. 1
   온도The mixture is heated over a steam bath until the internal mixture temperature
2. 2
   기타The mixture is then removed from the steam bath
3. 3
   workup.ADDITIONis treated with water (50 mL.) The layers
4. 4
   기타separated
5. 5
   건조the toluene phase is dried over anhydrous magnesium sulfate
6. 6
   농축is concentrated under reduced pressure
7. 7
   기타to afford an oil that
8. 8
   기타is purified by flash silica gel column chromatography
9. 9
   세척Elution through a 400 g Analogix silica cartridge with a gradient (100% hexanes to 35% ethyl acetate over 1800 mL, or three column volumes)
10. 10
    기타afforded an oily product
11. 11
    기타to afford a residue that solidified overnight under high vacuum to the solid product (32 g.)

실험 절차

Methyl 1-[3-(4-{[tert-butyl(dimethyl)silyl]oxy}phenyl)-5-hydroxy-4-phenyl-4,5-dihydroisoxazol-5-yl]cyclopropanecarboxylate (Compound C, 42 g) is dissolved in toluene (100 mL) and p-toluenesulfonic acid hydrate (1.7 g) is added with swirling. The mixture is heated over a steam bath until the internal mixture temperature, measured with a digital thermometer, is raised to 80° C. The mixture is then removed from the steam bath and is treated with water (50 mL.) The layers are shaken and separated and the toluene phase is dried over anhydrous magnesium sulfate and is concentrated under reduced pressure to afford an oil that is purified by flash silica gel column chromatography. Elution through a 400 g Analogix silica cartridge with a gradient (100% hexanes to 35% ethyl acetate over 1800 mL, or three column volumes) afforded an oily product. The product is dissolved in chloroform and is reconcentrated under reduced pressure to afford a residue that solidified overnight under high vacuum to the solid product (32 g.)

출처