2,2-Dimethoxypropane → 2-[(4R, 6S)-2,2-dimethyl-6-benzoyloxymethyl-1,3-dioxan-4-yl]acetic tert-butyl ester

Temperature

20 °C

To a solution composed of 8.94 g (27.6 mmol) of (5S)-6-benzoyloxy-3,5-dihydroxyhexanoic tert-butyl ester produced in Example 15, 35.8 mL of 2,2-dimethoxypropane, and 2.5 mL of methylene chloride was added 269 mg (1.4 mmol) of p-toluenesulfonic acid-1H2O, and the mixture was stirred at 20° C. for 4 hours, after which 500 mL of saturated sodium hydrogen carbonate solution was added. The aqueous layer was separated and further extracted with 2 portions of methylene chloride, 20 mL each, and the organic layers were combined. The combined solution was dehydrated over anhydrous sodium sulfate and the solvent was distilled off under reduced pressure to give a colorless oil. This residue was purified by silica gel column chromatography (Kieselgel 60, product of Merck; hexane:acetone=10:1) to give 7.24 g of 2-[(4R,6S)-2,2-dimethyl-6-benzoyloxymethyl-1,3-dioxan-4-yl]acetic tert-butyl ester (white solid). Yield: 72%.

1. customThe aqueous layer was separated
2. extractionfurther extracted with 2 portions of methylene chloride, 20 mL each
3. distillationthe solvent was distilled off under reduced pressure
4. customto give a colorless oil
5. customThis residue was purified by silica gel column chromatography (Kieselgel 60, product of Merck; hexane:acetone=10:1)

ORD record

ord-980177fca8a041c8ab1d3755eefdece6

Source dataset

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07094594B2