Methanol → benzyl-2(R)-[1(S)-(tert-butoxycarbonyl)-3-hydroxypropyl]-4-methylvalerate

A solution of 32.12 g of (E)-benzyl-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvalerate in 300 ml of dichloromethane was cooled to −78° C. and ozone was then bubbled through the mixture for 2.5 hours. 35 ml of dimethyl sulfide was then addded to the mixture and stirring continued overnight at room temperature. The solvent was evaporated to give an orange oil. This was dissolved in 300 ml of methanol, cooled to 0° C. under nitrogen and then treated portionwise with 5.6 g of sodium borohydride. The mixture was then quenched with glacial acetic acid and evaporated. The residue was dissolved in ethyl acetate and washed sequentially with 2M aqueous hydrogen chloride, water, 5% aqueous sodium hydrogen carbonate and brine and then dried over anhydrous magnesium sulfate. Filtration and evaporation gave a residue which was purified by flash column chromatography on silica gel, using ethyl acetate/hexane (2:8 increasing to 4:6) for the elution, to give 15.3 g of benzyl-2(R)-[1(S)-(tert-butoxycarbonyl)-3-hydroxypropyl]-4-methylvalerate in the form of a pale yellow oil.

1. customozone was then bubbled through the mixture for 2.5 hours
2. customThe solvent was evaporated
3. customto give an orange oil
4. temperaturecooled to 0° C. under nitrogen
5. customThe mixture was then quenched with glacial acetic acid
6. customevaporated
7. dissolutionThe residue was dissolved in ethyl acetate
8. washwashed sequentially with 2M aqueous hydrogen chloride, water, 5% aqueous sodium hydrogen carbonate and brine
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationFiltration and evaporation
11. customgave a residue which
12. customwas purified by flash column chromatography on silica gel
13. washfor the elution

ORD record

ord-b9b2d1c415104eb7962b9d748a520aaf

Source dataset

uspto-grants-2001_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06239151B1