Benzyl chloroformate → (3R,4R)-(1-benzyloxycarbonyl-4-hydroxypyrrolidin-3-yl)methanol

Sodium hydroxide (2.70 g) was dissolved in water (25 mL) and dioxane (15 mL) was added to the solution. (3R,4R)-(4-Hydroxypyrrolidin-3-yl)methanol (1.00 g) was then dissolved in the solution. While the mixture was chilled in an ice water bath, carbobenzoxy chloride (0.97 mL) was added dropwise. The reaction mixture was stirred at 5° C. or below for 1 hour and a second portion of carbobenzoxy chloride (0.97 mL) was added dropwise, followed by stirring at 5° C. or below for another hour and dropwise addition of a third portion of carbobenzoxy chloride (0.97 mL). The resulting mixture was stirred at 5° C. or below for 1 hour and then at room temperature for 1 hour. Subsequently, the reaction mixture was extracted with dichloromethane (2×100 mL). The dichloromethane layers were combined, dried over anhydrous sodium sulfate, concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluant: hexane:ethyl acetate=1:1->ethyl acetate:methanol=20:1) to give (3R,4R)-[1-benzyloxycarbonyl-4-hydroxypyrrolidin-3-yl]methanol as a milky white tar-like material (1.18 g).

1. temperatureWhile the mixture was chilled in an ice water bath
2. stirringby stirring at 5° C. or below for another hour
3. stirringThe resulting mixture was stirred at 5° C. or below for 1 hour
4. waitat room temperature for 1 hour
5. extractionSubsequently, the reaction mixture was extracted with dichloromethane (2×100 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe resulting residue was purified by silica gel column chromatography (eluant: hexane:ethyl acetate=1:1->ethyl acetate:methanol=20:1)

ORD record

ord-67925f87356f46f094dd00d73ee3abf3

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08106072B2