4-Methylquinoline → 5,6,7,8-Tetrahydro-4-methylquinoline

Using the general method of F. W. Vierhapper and E. L. Eliel (J. Org. Chem., 1975, 40, 2729), a solution of 4.97 g (34.7 mmol) of lepidine in 35 mL of trifluoroacetic acid was shaken with 580 mg of platinum oxide under 50 psi of hydrogen for 18 h. After filtering off the catalyst, the solution was concentrated to about 20 mL and diluted with 25 mL of water. The aquous solution was chilled in ice, and basified carefully with 35 mL of 50% aqueous sodium hydroxide. The aqeuous layer was then extracted with 4×50 mL of diethyl ether. The organic layers were dried over potassium hydroxide, decanted, and concentrated to yield 4.7 g (92% yield) of 4-methyl-5,6,7,8-tetrahydroquinoline as an amber oil.

1. filtrationAfter filtering off the catalyst
2. concentrationthe solution was concentrated to about 20 mL
3. additiondiluted with 25 mL of water
4. temperatureThe aquous solution was chilled in ice
5. extractionThe aqeuous layer was then extracted with 4×50 mL of diethyl ether
6. dry with materialThe organic layers were dried over potassium hydroxide
7. customdecanted
8. concentrationconcentrated

ORD record

ord-4ba0eea4fd304780acdc4cbe076072fa

Source dataset

uspto-grants-1999_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05972975