Reaction #452432

Reaction equation

1,4-cyclohexanedione mono-ethylene ketal

dimethylamine

sodium cyanoborohydride

→

title compound

Yield 85.0%

4-dimethylamino-1-cyclohexanone ethylene ketal

Yield 85.0%

Solvents

acetic acid

acetic acid

Conditions

Workup

1. 1
   workup.STIRRINGthe reaction stirred for an additional hour at ambient
2. 2
   workup.STIRRINGstirred 18 hours at ambient
3. 3
   OtherThe volatiles were removed under reduced pressure
4. 4
   workup.DISSOLUTIONthe residue dissolved in cold 5% tartaric acid solution
5. 5
   ExtractionThis aqueous phase was extracted well with dichloromethane
6. 6
   Concentrationconcentrated under reduced pressure

Procedure

To a solution of 5.0 gm (32 mMol) 1,4-cyclohexanedione mono-ethylene ketal and 10.80 gm (240 mMol) dimethylamine were added 2.0 mL acetic acid and the mixture was stirred at 0° C. for 1.5 hours. To this solution were then added 3.62 gm (58 mMol) sodium cyanoborohydride and the reaction stirred for an additional hour at ambient. The pH of the reaction mixture was adjusted to ~7 with 16 mL acetic acid and stirred 18 hours at ambient. The volatiles were removed under reduced pressure and the residue dissolved in cold 5% tartaric acid solution and then the aqueous phase was made basic with 5N sodium hydroxide. This aqueous phase was extracted well with dichloromethane. These organic extracts were combined and concentrated under reduced pressure to give 5.04 gm (85%) of the title compound as an oil.

Source