Chloroform → HCID 86757343, compound

187 mg of podophyllol ([α]D25=−180° (CHCl3, c 0.7)) incorporating two methyleneoxy bridges was prepared by the lithium aluminum hydride reduction of 205 mg of podophyllotoxin in dry tetrahydrofuran. Five drops of 1N aqueous hydrogen chloride was added to a solution of 185 mg of the podophyllol. The resulting mixture was stirred and heated to reflux under an atmosphere of nitrogen for 1 h. Thin layer chromatography on silica gel eluted with ethyl acetate indicated no podophyllol (Rf 0.35) remained. After cooling the mixture, it was washed three times with 15 mL portions of water. The combined aqueous wash was extracted three times with 10 mL portions of ethyl acetate. The combined ethyl acetate extract was added to the chloroform solution and the resulting mixture was washed once with 10 mL of water and then 10 mL of brine, and thereafter dried over anhydrous magnesium sulfate. Removal of the magnesium sulfate by filtration and evaporation of the solvent from the filtrate at reduced atmospheric pressure gave 153 mg of the 6-oxabicyclo[3.2.1]octane ([α]D=+183° (CHCl3, c 2.9); Rf 0.60, ethyl acetate) wherein the oxygen of the methyleneoxy bridge had bonded to the benzylic carbon. This intermediate was used in the next step without further purification.

1. temperatureheated
2. temperatureto reflux under an atmosphere of nitrogen for 1 h
3. washThin layer chromatography on silica gel eluted with ethyl acetate
4. temperatureAfter cooling the mixture, it
5. washwas washed three times with 15 mL portions of water
6. washThe combined aqueous wash
7. extractionwas extracted three times with 10 mL portions of ethyl acetate
8. extractionThe combined ethyl acetate extract
9. additionwas added to the chloroform solution
10. washthe resulting mixture was washed once with 10 mL of water
11. dry with material10 mL of brine, and thereafter dried over anhydrous magnesium sulfate
12. customRemoval of the magnesium sulfate
13. filtrationby filtration and evaporation of the solvent from the filtrate at reduced atmospheric pressure

ORD record

ord-ac226daec23c49b5a8d465f4e952110c

Source dataset

uspto-grants-2001_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06284789B1