Tetrahydrofuran → HCID 22672676, compound

Temperature

-78 °C

To a solution (10.72 ml, 1.0 mol/l, 10.72 mmol) of lithium hexamethyldisilazide in tetrahydrofuran was added tetrahydrofuran (60 ml), and the mixture was cooled to −78° C. To this solution was added dropwise a solution of 2-15 ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-ene (a mixture of exo form:endo form=7:3, 1.64 g, 9.75 mmol, obtained in Reference Example 1) in tetrahydrofuran (12 ml). After the dropwise addition, the mixture was heated to 0° C. and stirred for 1.5 h. To this reaction mixture was added saturated aqueous ammonium chloride solution (50 ml), and the mixture was extracted with chloroform (100 ml). The organic layer was partitioned, washed with saturated brine (20 ml), and dried over anhydrous sodium sulfate. The components having a low boiling point, such as the solvent and the like, were distilled away. The obtained residue was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=1/5 (volume ratio)) to give ethyl 5-hydroxy-1,3-cyclohexadiene-1-carboxylate (1.52 g, 9.06 mmol, yield 93.9).

1. additiona mixture of exo form
2. additionAfter the dropwise addition
3. temperaturethe mixture was heated to 0° C.
4. extractionthe mixture was extracted with chloroform (100 ml)
5. customThe organic layer was partitioned
6. washwashed with saturated brine (20 ml)
7. dry with materialdried over anhydrous sodium sulfate
8. distillationsuch as the solvent and the like, were distilled away
9. customThe obtained residue was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=1/5 (volume ratio))

ORD record

ord-1d685def54dc4539a7ffbb9c7a49de0f

Source dataset

uspto-grants-2004_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06790964B1