Reaktion #2467972

Reaktionsgleichung

K2CO3

dimethylamine

methyl 3-amino-5-phenylthiophene-2-carboxylate

HCl

NaNO2

→

solid

Ausbeute 76.0%

Methyl 3-[(dimethylamino)diazenyl]-5-phenylthiophene-2-carboxylate

Ausbeute 76.0%

Lösungsmittel

H2O

H2O

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISSOLUTIONto dissolve the product
2. 2
   workup.STIRRINGThe mixture was stirred at 0-5° C. for 1 h
3. 3
   workup.ADDITIONpoured into ice cold water
4. 4
   ExtraktionThe solution was extracted with chloroform (3×100 mL)
5. 5
   WaschenThe combined CHCl3 layer was washed with water, brine
6. 6
   Trocknendried over sodium sulfate
7. 7
   FiltrationThe solution was filtered
8. 8
   Sonstigeevaporated the solvent
9. 9
   SonstigeThe residue was chromatographed over silica gel column

Vorschrift

To a solution of methyl 3-amino-5-phenylthiophene-2-carboxylate (5 g, 21.4 mmol) and conc. HCl (9 mL, 85.8 mmol) in H2O (51 mL) was added acetone (30 mL) to dissolve the product. Then NaNO2 (1.7 g, 23.6 mmol) was added in portions for 15 min at 0° C. After stirring at 0-5° C. for 1 h, the reaction mixture was added to the solution of K2CO3 (11.2 g, 81.5 mmol) and dimethylamine (8.5 mL, 40%, 77.2 mmol) in H2O (60 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 (90:10) as eluents to give the product as a pale brown color solid (3.8 g, 76%), mp 92-94° C. 1H NMR (400 MHz, DMSO-d6): δ 7.78-7.80 (2H, m), 7.64 (1H, s), 7.46-7.52 (3H, m), 3.84 (3H, s), 3.60 (3H, s), 3.28 (3H, s); LC-MS (positive ion mode): m/z 290 (M+H)+.

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