Reacción #2467981

Ecuación de reacción

HCl

NaNO2

methyl 4-aminothiophene-2-carboxylate

K2CO3

dimethylamine

→

solid

Rendimiento 10.8%

Methyl 4-[(dimethylamino)diazenyl]thiophene-2-carboxylate

Rendimiento 10.8%

Disolventes

H2O

H2O

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGThe mixture was stirred at 0-5° C. for 1 h
2. 2
   workup.ADDITIONpoured into ice cold water
3. 3
   ExtracciónThe solution was extracted with chloroform (3×100 mL)
4. 4
   LavadoThe combined CHCl3 layer was washed with water, brine
5. 5
   Secadodried over sodium sulfate
6. 6
   FiltraciónThe solution was filtered
7. 7
   Otroevaporated the solvent
8. 8
   OtroThe residue was chromatographed over silica gel column

Procedimiento

To a solution of methyl 4-aminothiophene-2-carboxylate (1.7 g, 10.82 mmol) and cone. HCl (4.6 mL, 43.5 mmol) in H2O (20 mL) was added NaNO2 (0.84 g, 12.17 mmol) in portions for 5 min at 0° C. After stirring for 0.5 h at 0-5° C., the reaction mixture was added to the solution of K2CO3 (5.8 g, 42 mmol) and dimethylamine (4.6 mL, 40%, 40.9 mmol) in H2O (30 mL) at 0° C. The mixture was stirred at 0-5° C. for 1 h and poured into ice cold water. The solution was extracted with chloroform (3×100 mL). The combined CHCl3 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 hexane-EtOAc (80:20) as eluents to give the product as light red color solid (250 mg), which was recrystallized from chloroform-hexane (110 mg), mp 90-92° C. 1H NMR (400 MHz, CDCl3): δ 7.93 (1H, d, J=1.6 Hz), 7.31 (1H, d, J=1.6 Hz), 3.88 (3H, s), 3.31 (6H, br s).

Fuente