Reaction #1621985

Reaction equation

3,6-dimethyl-5-(4-methoxyphenyl)-3,4-dihydro-2-pyridone

→

3,6-dimethyl-5-(4-methoxyphenyl)-3,4,5,6-tetrahydro-2-pyridone

Yield 38.2%

Solvents

acetic acid

Conditions

Workup

1. 1
   Otherwas hydrogenated at room temperature
2. 2
   OtherThe catalyst was then removed by filtration
3. 3
   Otherthe glacial acetic acid was evaporated under reduced pressure
4. 4
   workup.DISSOLUTIONThe residue was dissolved in ethyl acetate
5. 5
   Washwashed successively with ammonia (5%), water
6. 6
   OtherThe organic layer was dried on sodium sulphate
7. 7
   Filtrationfiltered
8. 8
   Otherevaporated under reduced pressure
9. 9
   OtherThe resulting crude product (15 g) was purified chromatographically over a dry column of 700 g of silcagel (Merck, grain size 0.063-0.200 mm)
10. 10
    workup.ADDITIONa mixture of dichloromethane and acetone (95:5) as an eluent
11. 11
    OtherAfter evaporating the correct fractions

Procedure

1 g of platinum chloride was added to a solution of 15 g (65 mmol) of 3,6-dimethyl-5-(4-methoxyphenyl)-3,4-dihydro-2-pyridone (Synthesis 305, 1985) in 75 ml of glacial acetic acid and the mixture was hydrogenated at room temperature and a pressure of 52 psi for 8 hours. The catalyst was then removed by filtration and the glacial acetic acid was evaporated under reduced pressure. The residue was dissolved in ethyl acetate and washed successively with ammonia (5%), water and a saline solution. The organic layer was dried on sodium sulphate, filtered and evaporated under reduced pressure. The resulting crude product (15 g) was purified chromatographically over a dry column of 700 g of silcagel (Merck, grain size 0.063-0.200 mm) using a mixture of dichloromethane and acetone (95:5) as an eluent. After evaporating the correct fractions, 5.8 g (38%) of the desired 3,6-dimethyl-5-(4-methoxyphenyl)-3,4,5,6-tetrahydro-2-pyridone were obtained in addition to 3.5 g (23%) of the starting compound.

Source