Reaction #59343

Reaction equation

sodium hydroxide

cyanoacetic acid

acetic anhydride

1-isobutyl-3-methylthiourea

→

6-amino-1-isobutyl-3-methyl-2-thioxo-1H-pyrimidin-4-one

Yield 29.0%

Solvents

ethanol

Conditions

Workup

1. 1
   OtherThe solvent was evaporated
2. 2
   workup.DISSOLUTIONthe resulting red oil was redissolved in ethanol (5 mL)
3. 3
   TemperatureThe reaction mixture was refluxed for 2 h
4. 4
   Otherthe resulting pale brown solid was purified by flash chromatography (ethyl acetate)

Procedure

A solution of cyanoacetic acid (1.52 g, 17.8 mmol) in acetic anhydride (2.45 mL, 25.9 mmol) was added to 1-isobutyl-3-methylthiourea (2.37 g, 16.2 mmol). The reaction mixture was heated to 60° C. for 1.5 h. The solvent was evaporated and the resulting red oil was redissolved in ethanol (5 mL) and 5M sodium hydroxide (1.6 mL, 8.1 mmol) was added. The reaction mixture was refluxed for 2 h. The solvent was co-evaporated with ethanol and the resulting pale brown solid was purified by flash chromatography (ethyl acetate) to yield 6-amino-1-isobutyl-3-methyl-2-thioxo-1H-pyrimidin-4-one (1.0 g, 29%) as a yellow solid.

Source