Reaction #1144432

Reaction equation

acetic acid

lithium diisopropylamide

1-ethoxymethyl-5-ethyluracil

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

diphenyl disulfide

tetrahydrofuran

→

1-ethoxymethyl-5-ethyl-6-phenylthiouracil

Yield 32.0%

Solvents

ethyl acetate

Conditions

Workup

1. 1
   workup.ADDITIONwas added dropwise over 15 minute
2. 2
   Otherto react for 30 minutes
3. 3
   Otherbrought to room temperature
4. 4
   WashThe mixture was washed with water (3 mix 5) and saturated aqueous solution of sodium hydrogencarbonate (twice),
5. 5
   Otherdried on magnesium sulfate
6. 6
   Concentration′ concentrated under reduced pressure
7. 7
   OtherThe residue was purified by silica gel chromatography (ethyl acetate/hexane=3:17)
8. 8
   Othercrystallized from ethyl acetate

Procedure

Then, 2.2 ml of lithium diisopropylamide (4.4 mmol) solution in tetrahydrofuran (2.1M) was added to 6 ml of tetrahydrofuran under a nitrogen atmosphere at −70° C., to which a solution of 0.40 g (2.0 mmol) of 1-ethoxymethyl-5-ethyluracil in 3 ml of tetrahydrofuran was added dropwise over 15 minute. After stirring for 1 hour at −70° C., the reaction mixture was added with a solution of 0.57 g of diphenyl disulfide in 2 ml of tetrahydrofuran dropwise over 10 minutes and allowed to react for 30 minutes. The reaction mixture was added with 1 ml of acetic acid, brought to room temperature and then added with 30 ml of ethyl acetate. The mixture was washed with water (3 mix 5) and saturated aqueous solution of sodium hydrogencarbonate (twice), dried on magnesium sulfate and′ concentrated under reduced pressure. The residue was purified by silica gel chromatography (ethyl acetate/hexane=3:17) and crystallized from ethyl acetate to obtain 0.61 g of 1-ethoxymethyl-5-ethyl-6-phenylthiouracil (Yield: 32%).

Source