Reaction #2467988

Reaction equation

2,5-dihydroxy-1,4-dithiane

cyanoacetamide

→

solid

Yield 53.0%

2-Aminothiophene-3-carboxamide

Yield 53.0%

Solvents

ethanol

triethylamine

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was refluxed for 3 h
2. 2
   Otherattained to rt
3. 3
   OtherEthanol (appr. 150 mL) was removed under reduced pressure
4. 4
   workup.ADDITIONpoured the contents into ice cold water
5. 5
   ExtractionThe solution was extracted with ethyl acetate (3×100 mL)
6. 6
   Washthe combined EtOAc layer was washed with water, brine
7. 7
   Dryingdried over sodium sulfate
8. 8
   FiltrationThe solution was filtered
9. 9
   Otherevaporated the solvent
10. 10
    OtherThe residue was chromatographed over silica gel column

Procedure

To a solution of 2,5-dihydroxy-1,4-dithiane (10 g, 65.78 mmol) in ethanol (200 mL) and triethylamine (2 mL) was added cyanoacetamide (5.52 g, 65.78 mmol) at rt for 5 min. The reaction mixture was refluxed for 3 h and attained to rt. Ethanol (appr. 150 mL) was removed under reduced pressure and poured the contents into ice cold water and stirred for 15 min. The solution was extracted with ethyl acetate (3×100 mL) and the combined EtOAc layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent. The residue was chromatographed over silica gel column using chloroform-methanol (95:5) as eluents to give the product as a pale yellow color solid (4.9 g, 53%), mp 150-152° C.

Source